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    <link:label xlink:label="apt_DocumentAndEntityInformation-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Document And Entity Information</link:label>
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    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate</link:label>
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    <link:label xlink:label="apt_NoteToFinancialStatementDetailsTextual-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note To Financial Statement Details Textual</link:label>
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    <link:loc xlink:href="apt-20201231.xsd#apt_statement-statement-significant-accounting-policies-policies" xlink:label="apt_statement-statement-significant-accounting-policies-policies" xlink:type="locator"/>
    <link:label xlink:label="apt_statement-statement-significant-accounting-policies-policies-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Significant Accounting Policies</link:label>
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    <link:loc xlink:href="apt-20201231.xsd#apt_statement-statement-note-2-summary-of-significant-accounting-policies-tables" xlink:label="apt_statement-statement-note-2-summary-of-significant-accounting-policies-tables" xlink:type="locator"/>
    <link:label xlink:label="apt_statement-statement-note-2-summary-of-significant-accounting-policies-tables-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 2 - Summary of Significant Accounting Policies</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate" xlink:label="us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income taxes based on U.S. statutory rate of 21% and 34%, respectively</link:label>
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    <link:label xlink:label="apt_statement-statement-note-4-inventories-tables-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 4 - Inventories</link:label>
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    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Risk-free interest rate</link:label>
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    <link:loc xlink:href="apt-20201231.xsd#apt_statement-statement-note-5-property-and-equipment-tables" xlink:label="apt_statement-statement-note-5-property-and-equipment-tables" xlink:type="locator"/>
    <link:label xlink:label="apt_statement-statement-note-5-property-and-equipment-tables-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 5 - Property and Equipment</link:label>
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    <link:loc xlink:href="apt-20201231.xsd#apt_statement-statement-note-6-goodwill-and-intangible-assets-tables" xlink:label="apt_statement-statement-note-6-goodwill-and-intangible-assets-tables" xlink:type="locator"/>
    <link:label xlink:label="apt_statement-statement-note-6-goodwill-and-intangible-assets-tables-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 6 - Goodwill and Intangible Assets</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_statement-statement-note-6-goodwill-and-intangible-assets-tables" xlink:to="apt_statement-statement-note-6-goodwill-and-intangible-assets-tables-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_statement-statement-note-8-accrued-liabilities-tables" xlink:label="apt_statement-statement-note-8-accrued-liabilities-tables" xlink:type="locator"/>
    <link:label xlink:label="apt_statement-statement-note-8-accrued-liabilities-tables-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 8 - Accrued Liabilities</link:label>
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    <link:loc xlink:href="apt-20201231.xsd#apt_statement-statement-note-10-shareholders-equity-tables" xlink:label="apt_statement-statement-note-10-shareholders-equity-tables" xlink:type="locator"/>
    <link:label xlink:label="apt_statement-statement-note-10-shareholders-equity-tables-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 10 - Shareholders' Equity</link:label>
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    <link:loc xlink:href="apt-20201231.xsd#apt_statement-statement-note-11-income-taxes-tables" xlink:label="apt_statement-statement-note-11-income-taxes-tables" xlink:type="locator"/>
    <link:label xlink:label="apt_statement-statement-note-11-income-taxes-tables-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 11 - Income Taxes</link:label>
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    <link:loc xlink:href="apt-20201231.xsd#apt_statement-statement-note-12-leases-tables" xlink:label="apt_statement-statement-note-12-leases-tables" xlink:type="locator"/>
    <link:label xlink:label="apt_statement-statement-note-12-leases-tables-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 12 - Leases</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxDisclosureTextBlock" xlink:label="us-gaap_IncomeTaxDisclosureTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IncomeTaxDisclosureTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Tax Disclosure [Text Block]</link:label>
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    <link:loc xlink:href="apt-20201231.xsd#apt_statement-statement-note-15-activity-of-business-segments-tables" xlink:label="apt_statement-statement-note-15-activity-of-business-segments-tables" xlink:type="locator"/>
    <link:label xlink:label="apt_statement-statement-note-15-activity-of-business-segments-tables-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 15 - Activity of Business Segments</link:label>
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    <link:loc xlink:href="apt-20201231.xsd#apt_statement-statement-note-16-concentration-of-risk-tables" xlink:label="apt_statement-statement-note-16-concentration-of-risk-tables" xlink:type="locator"/>
    <link:label xlink:label="apt_statement-statement-note-16-concentration-of-risk-tables-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 16 - Concentration of Risk</link:label>
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    <link:loc xlink:href="apt-20201231.xsd#apt_statement-statement-note-2-summary-of-significant-accounting-policies-property-and-equipment-details" xlink:label="apt_statement-statement-note-2-summary-of-significant-accounting-policies-property-and-equipment-details" xlink:type="locator"/>
    <link:label xlink:label="apt_statement-statement-note-2-summary-of-significant-accounting-policies-property-and-equipment-details-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 2 - Summary of Significant Accounting Policies - Property and Equipment (Details)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_statement-statement-note-2-summary-of-significant-accounting-policies-property-and-equipment-details" xlink:to="apt_statement-statement-note-2-summary-of-significant-accounting-policies-property-and-equipment-details-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_statement-statement-note-2-summary-of-significant-accounting-policies-reconciliation-of-net-income-and-number-of-shares-used-in-computations-of-basic-and-diluted-eps-details" xlink:label="apt_statement-statement-note-2-summary-of-significant-accounting-policies-reconciliation-of-net-income-and-number-of-shares-used-in-computations-of-basic-and-diluted-eps-details" xlink:type="locator"/>
    <link:label xlink:label="apt_statement-statement-note-2-summary-of-significant-accounting-policies-reconciliation-of-net-income-and-number-of-shares-used-in-computations-of-basic-and-diluted-eps-details-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 2 - Summary of Significant Accounting Policies - Reconciliation of Net Income and Number of Shares Used in Computations of Basic and Diluted EPS (Details)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_statement-statement-note-2-summary-of-significant-accounting-policies-reconciliation-of-net-income-and-number-of-shares-used-in-computations-of-basic-and-diluted-eps-details" xlink:to="apt_statement-statement-note-2-summary-of-significant-accounting-policies-reconciliation-of-net-income-and-number-of-shares-used-in-computations-of-basic-and-diluted-eps-details-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Expected volatility</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_statement-statement-note-2-summary-of-significant-accounting-policies-fair-value-of-financial-assets-details" xlink:label="apt_statement-statement-note-2-summary-of-significant-accounting-policies-fair-value-of-financial-assets-details" xlink:type="locator"/>
    <link:label xlink:label="apt_statement-statement-note-2-summary-of-significant-accounting-policies-fair-value-of-financial-assets-details-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 2 - Summary of Significant Accounting Policies - Fair Value of Financial Assets (Details)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_statement-statement-note-2-summary-of-significant-accounting-policies-fair-value-of-financial-assets-details" xlink:to="apt_statement-statement-note-2-summary-of-significant-accounting-policies-fair-value-of-financial-assets-details-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="us-gaap_LiabilitiesCurrent" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_LiabilitiesCurrent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_LiabilitiesCurrent</link:label>
    <link:label xlink:label="us-gaap_LiabilitiesCurrent-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total current liabilities</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="us-gaap_LiabilitiesCurrent-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_statement-statement-note-4-inventories-inventories-details" xlink:label="apt_statement-statement-note-4-inventories-inventories-details" xlink:type="locator"/>
    <link:label xlink:label="apt_statement-statement-note-4-inventories-inventories-details-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 4 - Inventories - Inventories (Details)</link:label>
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    <link:label xlink:label="apt_statement-statement-note-5-property-and-equipment-property-and-equipment-details-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 5 - Property and Equipment - Property and Equipment (Details)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_statement-statement-note-5-property-and-equipment-property-and-equipment-details" xlink:to="apt_statement-statement-note-5-property-and-equipment-property-and-equipment-details-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_statement-statement-note-6-goodwill-and-intangible-assets-definitelived-intangible-assets-details" xlink:label="apt_statement-statement-note-6-goodwill-and-intangible-assets-definitelived-intangible-assets-details" xlink:type="locator"/>
    <link:label xlink:label="apt_statement-statement-note-6-goodwill-and-intangible-assets-definitelived-intangible-assets-details-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 6 - Goodwill and Intangible Assets - Definite-lived Intangible Assets (Details)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_statement-statement-note-6-goodwill-and-intangible-assets-definitelived-intangible-assets-details" xlink:to="apt_statement-statement-note-6-goodwill-and-intangible-assets-definitelived-intangible-assets-details-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_statement-statement-note-6-goodwill-and-intangible-assets-estimated-future-amortization-expense-related-to-definitelived-intangible-assets-details" xlink:label="apt_statement-statement-note-6-goodwill-and-intangible-assets-estimated-future-amortization-expense-related-to-definitelived-intangible-assets-details" xlink:type="locator"/>
    <link:label xlink:label="apt_statement-statement-note-6-goodwill-and-intangible-assets-estimated-future-amortization-expense-related-to-definitelived-intangible-assets-details-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 6 - Goodwill and Intangible Assets - Estimated Future Amortization Expense Related to Definite-lived Intangible Assets (Details)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_statement-statement-note-6-goodwill-and-intangible-assets-estimated-future-amortization-expense-related-to-definitelived-intangible-assets-details" xlink:to="apt_statement-statement-note-6-goodwill-and-intangible-assets-estimated-future-amortization-expense-related-to-definitelived-intangible-assets-details-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Expected life in years (Year)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_statement-statement-note-8-accrued-liabilities-accrued-liabilities-details" xlink:label="apt_statement-statement-note-8-accrued-liabilities-accrued-liabilities-details" xlink:type="locator"/>
    <link:label xlink:label="apt_statement-statement-note-8-accrued-liabilities-accrued-liabilities-details-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 8 - Accrued Liabilities - Accrued Liabilities (Details)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_statement-statement-note-8-accrued-liabilities-accrued-liabilities-details" xlink:to="apt_statement-statement-note-8-accrued-liabilities-accrued-liabilities-details-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_statement-statement-note-10-shareholders-equity-stock-option-activity-details" xlink:label="apt_statement-statement-note-10-shareholders-equity-stock-option-activity-details" xlink:type="locator"/>
    <link:label xlink:label="apt_statement-statement-note-10-shareholders-equity-stock-option-activity-details-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 10 - Shareholders' Equity - Stock Option Activity (Details)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_statement-statement-note-10-shareholders-equity-stock-option-activity-details" xlink:to="apt_statement-statement-note-10-shareholders-equity-stock-option-activity-details-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_statement-statement-note-10-shareholders-equity-stock-option-valuation-assumptions-details" xlink:label="apt_statement-statement-note-10-shareholders-equity-stock-option-valuation-assumptions-details" xlink:type="locator"/>
    <link:label xlink:label="apt_statement-statement-note-10-shareholders-equity-stock-option-valuation-assumptions-details-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 10 - Shareholders' Equity - Stock Option Valuation Assumptions (Details)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_statement-statement-note-10-shareholders-equity-stock-option-valuation-assumptions-details" xlink:to="apt_statement-statement-note-10-shareholders-equity-stock-option-valuation-assumptions-details-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_statement-statement-note-10-shareholders-equity-information-about-stock-options-details" xlink:label="apt_statement-statement-note-10-shareholders-equity-information-about-stock-options-details" xlink:type="locator"/>
    <link:label xlink:label="apt_statement-statement-note-10-shareholders-equity-information-about-stock-options-details-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 10 - Shareholders' Equity - Information About Stock Options (Details)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_statement-statement-note-10-shareholders-equity-information-about-stock-options-details" xlink:to="apt_statement-statement-note-10-shareholders-equity-information-about-stock-options-details-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_statement-statement-note-11-income-taxes-provision-for-income-taxes-details" xlink:label="apt_statement-statement-note-11-income-taxes-provision-for-income-taxes-details" xlink:type="locator"/>
    <link:label xlink:label="apt_statement-statement-note-11-income-taxes-provision-for-income-taxes-details-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 11 - Income Taxes - Provision for Income Taxes (Details)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_statement-statement-note-11-income-taxes-provision-for-income-taxes-details" xlink:to="apt_statement-statement-note-11-income-taxes-provision-for-income-taxes-details-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock" xlink:label="us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock" xlink:to="us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_statement-statement-note-11-income-taxes-deferred-income-tax-assets-details" xlink:label="apt_statement-statement-note-11-income-taxes-deferred-income-tax-assets-details" xlink:type="locator"/>
    <link:label xlink:label="apt_statement-statement-note-11-income-taxes-deferred-income-tax-assets-details-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 11 - Income Taxes - Deferred Income Tax Assets (Details)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_statement-statement-note-11-income-taxes-deferred-income-tax-assets-details" xlink:to="apt_statement-statement-note-11-income-taxes-deferred-income-tax-assets-details-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_statement-statement-note-11-income-taxes-income-tax-reconciliation-details" xlink:label="apt_statement-statement-note-11-income-taxes-income-tax-reconciliation-details" xlink:type="locator"/>
    <link:label xlink:label="apt_statement-statement-note-11-income-taxes-income-tax-reconciliation-details-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 11 - Income Taxes - Income Tax Reconciliation (Details)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_statement-statement-note-11-income-taxes-income-tax-reconciliation-details" xlink:to="apt_statement-statement-note-11-income-taxes-income-tax-reconciliation-details-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_statement-statement-note-12-leases-future-minimum-lease-payment-details" xlink:label="apt_statement-statement-note-12-leases-future-minimum-lease-payment-details" xlink:type="locator"/>
    <link:label xlink:label="apt_statement-statement-note-12-leases-future-minimum-lease-payment-details-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 12 - Leases - Future Minimum Lease Payment (Details)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_statement-statement-note-12-leases-future-minimum-lease-payment-details" xlink:to="apt_statement-statement-note-12-leases-future-minimum-lease-payment-details-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_statement-statement-note-15-activity-of-business-segments-consolidated-net-sales-details" xlink:label="apt_statement-statement-note-15-activity-of-business-segments-consolidated-net-sales-details" xlink:type="locator"/>
    <link:label xlink:label="apt_statement-statement-note-15-activity-of-business-segments-consolidated-net-sales-details-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 15 - Activity of Business Segments - Consolidated Net Sales (Details)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_statement-statement-note-15-activity-of-business-segments-consolidated-net-sales-details" xlink:to="apt_statement-statement-note-15-activity-of-business-segments-consolidated-net-sales-details-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_statement-statement-note-15-activity-of-business-segments-reconciliation-of-total-segment-income-to-total-consolidated-net-income-details" xlink:label="apt_statement-statement-note-15-activity-of-business-segments-reconciliation-of-total-segment-income-to-total-consolidated-net-income-details" xlink:type="locator"/>
    <link:label xlink:label="apt_statement-statement-note-15-activity-of-business-segments-reconciliation-of-total-segment-income-to-total-consolidated-net-income-details-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 15 - Activity of Business Segments - Reconciliation of Total Segment Income to Total Consolidated Net Income (Details)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_statement-statement-note-15-activity-of-business-segments-reconciliation-of-total-segment-income-to-total-consolidated-net-income-details" xlink:to="apt_statement-statement-note-15-activity-of-business-segments-reconciliation-of-total-segment-income-to-total-consolidated-net-income-details-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" xlink:label="us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Payment Arrangement, Option, Activity [Table Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" xlink:to="us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_statement-statement-note-15-activity-of-business-segments-consolidated-net-sales-and-longlived-asset-information-by-geographic-area-details" xlink:label="apt_statement-statement-note-15-activity-of-business-segments-consolidated-net-sales-and-longlived-asset-information-by-geographic-area-details" xlink:type="locator"/>
    <link:label xlink:label="apt_statement-statement-note-15-activity-of-business-segments-consolidated-net-sales-and-longlived-asset-information-by-geographic-area-details-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 15 - Activity of Business Segments - Consolidated Net Sales and Long-lived Asset Information by Geographic Area (Details)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_statement-statement-note-15-activity-of-business-segments-consolidated-net-sales-and-longlived-asset-information-by-geographic-area-details" xlink:to="apt_statement-statement-note-15-activity-of-business-segments-consolidated-net-sales-and-longlived-asset-information-by-geographic-area-details-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationActivityTableTextBlock" xlink:label="us-gaap_ScheduleOfShareBasedCompensationActivityTableTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ScheduleOfShareBasedCompensationActivityTableTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Payment Arrangement, Activity [Table Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfShareBasedCompensationActivityTableTextBlock" xlink:to="us-gaap_ScheduleOfShareBasedCompensationActivityTableTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_statement-statement-note-15-activity-of-business-segments-consolidated-net-property-and-equipment-goodwill-and-intangible-assets-details" xlink:label="apt_statement-statement-note-15-activity-of-business-segments-consolidated-net-property-and-equipment-goodwill-and-intangible-assets-details" xlink:type="locator"/>
    <link:label xlink:label="apt_statement-statement-note-15-activity-of-business-segments-consolidated-net-property-and-equipment-goodwill-and-intangible-assets-details-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 15 - Activity of Business Segments - Consolidated Net Property and Equipment, Goodwill and Intangible Assets (Details)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_statement-statement-note-15-activity-of-business-segments-consolidated-net-property-and-equipment-goodwill-and-intangible-assets-details" xlink:to="apt_statement-statement-note-15-activity-of-business-segments-consolidated-net-property-and-equipment-goodwill-and-intangible-assets-details-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_statement-statement-note-16-concentration-of-risk-customer-concentration-details" xlink:label="apt_statement-statement-note-16-concentration-of-risk-customer-concentration-details" xlink:type="locator"/>
    <link:label xlink:label="apt_statement-statement-note-16-concentration-of-risk-customer-concentration-details-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Note 16 - Concentration of Risk - Customer Concentration (Details)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_statement-statement-note-16-concentration-of-risk-customer-concentration-details" xlink:to="apt_statement-statement-note-16-concentration-of-risk-customer-concentration-details-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_AlphaProTechEngineeredProductsMember" xlink:label="apt_AlphaProTechEngineeredProductsMember" xlink:type="locator"/>
    <link:label xlink:label="apt_AlphaProTechEngineeredProductsMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Alpha Pro Tech Engineered Products [Member]</link:label>
    <link:label xlink:label="apt_AlphaProTechEngineeredProductsMember-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Alpha ProTech Engineered Products [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_AlphaProTechEngineeredProductsMember" xlink:to="apt_AlphaProTechEngineeredProductsMember-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_NotesToFinancialStatements" xlink:label="apt_NotesToFinancialStatements" xlink:type="locator"/>
    <link:label xlink:label="apt_NotesToFinancialStatements-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Notes To Financial Statements</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_NotesToFinancialStatements" xlink:to="apt_NotesToFinancialStatements-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_ExpenseToAcquireInventory" xlink:label="apt_ExpenseToAcquireInventory" xlink:type="locator"/>
    <link:label xlink:label="apt_ExpenseToAcquireInventory-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">apt_ExpenseToAcquireInventory</link:label>
    <link:label xlink:label="apt_ExpenseToAcquireInventory-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Expense To Acquire Inventory</link:label>
    <link:label xlink:label="apt_ExpenseToAcquireInventory-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Purchases from our Joint venture.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_ExpenseToAcquireInventory" xlink:to="apt_ExpenseToAcquireInventory-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_NotesToFinancialStatementsAbstract" xlink:label="apt_NotesToFinancialStatementsAbstract" xlink:type="locator"/>
    <link:label xlink:label="apt_NotesToFinancialStatementsAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Notes To Financial Statements [Abstract]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_NotesToFinancialStatementsAbstract" xlink:to="apt_NotesToFinancialStatementsAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_CumulativeEquityInIncomeOfUnconsolidatedAffiliate" xlink:label="apt_CumulativeEquityInIncomeOfUnconsolidatedAffiliate" xlink:type="locator"/>
    <link:label xlink:label="apt_CumulativeEquityInIncomeOfUnconsolidatedAffiliate-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">apt_CumulativeEquityInIncomeOfUnconsolidatedAffiliate</link:label>
    <link:label xlink:label="apt_CumulativeEquityInIncomeOfUnconsolidatedAffiliate-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cumulative Equity In Income Of Unconsolidated Affiliate</link:label>
    <link:label xlink:label="apt_CumulativeEquityInIncomeOfUnconsolidatedAffiliate-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">CumulativeEquityInIncomeOfUnconsolidatedAffiliate</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_CumulativeEquityInIncomeOfUnconsolidatedAffiliate" xlink:to="apt_CumulativeEquityInIncomeOfUnconsolidatedAffiliate-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_BuildingSupplyMember" xlink:label="apt_BuildingSupplyMember" xlink:type="locator"/>
    <link:label xlink:label="apt_BuildingSupplyMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Building Supply [Member]</link:label>
    <link:label xlink:label="apt_BuildingSupplyMember-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Building Supply [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_BuildingSupplyMember" xlink:to="apt_BuildingSupplyMember-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_DisposableProtectiveApparelMember" xlink:label="apt_DisposableProtectiveApparelMember" xlink:type="locator"/>
    <link:label xlink:label="apt_DisposableProtectiveApparelMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposable Protective Apparel [Member]</link:label>
    <link:label xlink:label="apt_DisposableProtectiveApparelMember-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Disposable Protective Apparel [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_DisposableProtectiveApparelMember" xlink:to="apt_DisposableProtectiveApparelMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt" xlink:label="us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds from sales of marketable securities</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt" xlink:to="us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_TotalConsolidatedAssets" xlink:label="apt_TotalConsolidatedAssets" xlink:type="locator"/>
    <link:label xlink:label="apt_TotalConsolidatedAssets-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Consolidated assets</link:label>
    <link:label xlink:label="apt_TotalConsolidatedAssets-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Total consolidated assets</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_TotalConsolidatedAssets" xlink:to="apt_TotalConsolidatedAssets-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Options exercisable (in dollars per share)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Options Exercisable, Aggregate Intrinsic Value</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue</link:label>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Options exercisable (in shares)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Options Outstanding, Aggregate Intrinsic Value</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice</link:label>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice-label" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xml:lang="en-US">Options outstanding (in dollars per share)</link:label>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice-label" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">Options outstanding (in dollars per share)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ContractWithCustomerLiabilityCurrent" xlink:label="us-gaap_ContractWithCustomerLiabilityCurrent" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ContractWithCustomerLiabilityCurrent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Customer advance payments of orders</link:label>
    <link:label xlink:label="us-gaap_ContractWithCustomerLiabilityCurrent-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Contract with Customer, Liability, Current</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ContractWithCustomerLiabilityCurrent" xlink:to="us-gaap_ContractWithCustomerLiabilityCurrent-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Canceled/expired/forfeited (in dollars per share)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GoodwillAndIntangibleAssetsDisclosureTextBlock" xlink:label="us-gaap_GoodwillAndIntangibleAssetsDisclosureTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_GoodwillAndIntangibleAssetsDisclosureTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Goodwill and Intangible Assets Disclosure [Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GoodwillAndIntangibleAssetsDisclosureTextBlock" xlink:to="us-gaap_GoodwillAndIntangibleAssetsDisclosureTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Granted to employees and directors (in dollars per share)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Exercised (in dollars per share)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccruedLiabilitiesCurrent" xlink:label="us-gaap_AccruedLiabilitiesCurrent" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AccruedLiabilitiesCurrent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accrued liabilities</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccruedLiabilitiesCurrent" xlink:to="us-gaap_AccruedLiabilitiesCurrent-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeasesTextBlock" xlink:label="us-gaap_LesseeOperatingLeasesTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_LesseeOperatingLeasesTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessee, Operating Leases [Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LesseeOperatingLeasesTextBlock" xlink:to="us-gaap_LesseeOperatingLeasesTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsPayableCurrent" xlink:label="us-gaap_AccountsPayableCurrent" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AccountsPayableCurrent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounts payable</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccountsPayableCurrent" xlink:to="us-gaap_AccountsPayableCurrent-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromSaleOfProductiveAssets" xlink:label="us-gaap_ProceedsFromSaleOfProductiveAssets" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ProceedsFromSaleOfProductiveAssets-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_ProceedsFromSaleOfProductiveAssets</link:label>
    <link:label xlink:label="us-gaap_ProceedsFromSaleOfProductiveAssets-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from Sale of Productive Assets, Total</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromSaleOfProductiveAssets" xlink:to="us-gaap_ProceedsFromSaleOfProductiveAssets-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber</link:label>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)</link:label>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber-label" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xml:lang="en-US">Options outstanding (in shares)</link:label>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber-label" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">Options outstanding (in shares)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_MarketableSecuritiesMember" xlink:label="apt_MarketableSecuritiesMember" xlink:type="locator"/>
    <link:label xlink:label="apt_MarketableSecuritiesMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Marketable Securities [Member]</link:label>
    <link:label xlink:label="apt_MarketableSecuritiesMember-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Marketable securities [member</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_MarketableSecuritiesMember" xlink:to="apt_MarketableSecuritiesMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetirementPlanTypeAxis" xlink:label="us-gaap_RetirementPlanTypeAxis" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_RetirementPlanTypeAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Retirement Plan Type [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RetirementPlanTypeAxis" xlink:to="us-gaap_RetirementPlanTypeAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccruedBonusesCurrent" xlink:label="us-gaap_AccruedBonusesCurrent" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AccruedBonusesCurrent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Commission and bonuses payable and general accrued liabilities</link:label>
    <link:label xlink:label="us-gaap_AccruedBonusesCurrent-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accrued Bonuses, Current</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccruedBonusesCurrent" xlink:to="us-gaap_AccruedBonusesCurrent-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetirementPlanTypeDomain" xlink:label="us-gaap_RetirementPlanTypeDomain" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_RetirementPlanTypeDomain-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Retirement Plan Type [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RetirementPlanTypeDomain" xlink:to="us-gaap_RetirementPlanTypeDomain-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod</link:label>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod-label" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Canceled/expired/forfeited (in shares)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccruedSalariesCurrent" xlink:label="us-gaap_AccruedSalariesCurrent" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AccruedSalariesCurrent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payroll expenses and tax payable</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccruedSalariesCurrent" xlink:to="us-gaap_AccruedSalariesCurrent-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PolicyTextBlockAbstract" xlink:label="us-gaap_PolicyTextBlockAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PolicyTextBlockAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_PolicyTextBlockAbstract</link:label>
    <link:label xlink:label="us-gaap_PolicyTextBlockAbstract-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accounting Policies</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PolicyTextBlockAbstract" xlink:to="us-gaap_PolicyTextBlockAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleGainLoss" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleGainLoss" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DebtSecuritiesAvailableForSaleGainLoss-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gain (loss) on marketable securities</link:label>
    <link:label xlink:label="us-gaap_DebtSecuritiesAvailableForSaleGainLoss-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt Securities, Available-for-sale, Gain (Loss), Total</link:label>
    <link:label xlink:label="us-gaap_DebtSecuritiesAvailableForSaleGainLoss-label" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">(Gain) Loss on marketable securities</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtSecuritiesAvailableForSaleGainLoss" xlink:to="us-gaap_DebtSecuritiesAvailableForSaleGainLoss-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleRealizedGain" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleRealizedGain" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DebtSecuritiesAvailableForSaleRealizedGain-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_DebtSecuritiesAvailableForSaleRealizedGain</link:label>
    <link:label xlink:label="us-gaap_DebtSecuritiesAvailableForSaleRealizedGain-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt Securities, Available-for-sale, Realized Gain</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtSecuritiesAvailableForSaleRealizedGain" xlink:to="us-gaap_DebtSecuritiesAvailableForSaleRealizedGain-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedGainLoss" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleUnrealizedGainLoss" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DebtSecuritiesAvailableForSaleUnrealizedGainLoss-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_DebtSecuritiesAvailableForSaleUnrealizedGainLoss</link:label>
    <link:label xlink:label="us-gaap_DebtSecuritiesAvailableForSaleUnrealizedGainLoss-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt Securities, Available-for-sale, Unrealized Gain (Loss), Total</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtSecuritiesAvailableForSaleUnrealizedGainLoss" xlink:to="us-gaap_DebtSecuritiesAvailableForSaleUnrealizedGainLoss-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant</link:label>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleRealizedLoss" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleRealizedLoss" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DebtSecuritiesAvailableForSaleRealizedLoss-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_DebtSecuritiesAvailableForSaleRealizedLoss</link:label>
    <link:label xlink:label="us-gaap_DebtSecuritiesAvailableForSaleRealizedLoss-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt Securities, Available-for-sale, Realized Loss</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtSecuritiesAvailableForSaleRealizedLoss" xlink:to="us-gaap_DebtSecuritiesAvailableForSaleRealizedLoss-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_ManufacturingCoatedMaterialAndSewingProprietaryDisposableProtectiveApparelMember" xlink:label="apt_ManufacturingCoatedMaterialAndSewingProprietaryDisposableProtectiveApparelMember" xlink:type="locator"/>
    <link:label xlink:label="apt_ManufacturingCoatedMaterialAndSewingProprietaryDisposableProtectiveApparelMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Manufacturing Coated Material and Sewing Proprietary Disposable Protective Apparel [Member]</link:label>
    <link:label xlink:label="apt_ManufacturingCoatedMaterialAndSewingProprietaryDisposableProtectiveApparelMember-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Indicates a facility used for manufacturing coated material and sewing proprietary disposable protective apparel.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_ManufacturingCoatedMaterialAndSewingProprietaryDisposableProtectiveApparelMember" xlink:to="apt_ManufacturingCoatedMaterialAndSewingProprietaryDisposableProtectiveApparelMember-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_SewingProprietaryDisposableProtectiveApparelMember" xlink:label="apt_SewingProprietaryDisposableProtectiveApparelMember" xlink:type="locator"/>
    <link:label xlink:label="apt_SewingProprietaryDisposableProtectiveApparelMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sewing Proprietary Disposable Protective Apparel [Member]</link:label>
    <link:label xlink:label="apt_SewingProprietaryDisposableProtectiveApparelMember-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Indicates a facility used for sewing proprietary disposable protective apparel.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_SewingProprietaryDisposableProtectiveApparelMember" xlink:to="apt_SewingProprietaryDisposableProtectiveApparelMember-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_ManufacturingBuildingProductsMember" xlink:label="apt_ManufacturingBuildingProductsMember" xlink:type="locator"/>
    <link:label xlink:label="apt_ManufacturingBuildingProductsMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Manufacturing Building Products [Member]</link:label>
    <link:label xlink:label="apt_ManufacturingBuildingProductsMember-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Indicates a facility used for manufacturing building products.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_ManufacturingBuildingProductsMember" xlink:to="apt_ManufacturingBuildingProductsMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_PaymentsToAcquirePropertyPlantAndEquipment</link:label>
    <link:label xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment-label" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Purchase of property and equipment</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:to="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements" xlink:label="us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Add: Dilutive effect of common stock options (in shares)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements" xlink:to="us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_ManufacturingOfBuildingProductsMember" xlink:label="apt_ManufacturingOfBuildingProductsMember" xlink:type="locator"/>
    <link:label xlink:label="apt_ManufacturingOfBuildingProductsMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Manufacturing Of Building Products [Member]</link:label>
    <link:label xlink:label="apt_ManufacturingOfBuildingProductsMember-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Indicates a facility used for manufacturing of building products.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_ManufacturingOfBuildingProductsMember" xlink:to="apt_ManufacturingOfBuildingProductsMember-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_EmploymentAgreementTerm" xlink:label="apt_EmploymentAgreementTerm" xlink:type="locator"/>
    <link:label xlink:label="apt_EmploymentAgreementTerm-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">apt_EmploymentAgreementTerm</link:label>
    <link:label xlink:label="apt_EmploymentAgreementTerm-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Employment Agreement Term (Year)</link:label>
    <link:label xlink:label="apt_EmploymentAgreementTerm-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Period of the employment agreement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_EmploymentAgreementTerm" xlink:to="apt_EmploymentAgreementTerm-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod</link:label>
    <link:label xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1</link:label>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilitiesCurrentAbstract" xlink:label="us-gaap_LiabilitiesCurrentAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_LiabilitiesCurrentAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Current liabilities:</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LiabilitiesCurrentAbstract" xlink:to="us-gaap_LiabilitiesCurrentAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Shares (denominator):</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract" xlink:to="us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Assets" xlink:label="us-gaap_Assets" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_Assets-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_Assets</link:label>
    <link:label xlink:label="us-gaap_Assets-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Assets, Total</link:label>
    <link:label xlink:label="us-gaap_Assets-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total assets</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_Assets" xlink:to="us-gaap_Assets-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SupplementalCashFlowInformationAbstract" xlink:label="us-gaap_SupplementalCashFlowInformationAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_SupplementalCashFlowInformationAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Supplemental disclosure of cash flow information:</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SupplementalCashFlowInformationAbstract" xlink:to="us-gaap_SupplementalCashFlowInformationAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="us-gaap_PlanNameAxis" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PlanNameAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Plan Name [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PlanNameAxis" xlink:to="us-gaap_PlanNameAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="us-gaap_PlanNameDomain" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PlanNameDomain-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Plan Name [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PlanNameDomain" xlink:to="us-gaap_PlanNameDomain-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareholdersEquityAndShareBasedPaymentsTextBlock" xlink:label="us-gaap_ShareholdersEquityAndShareBasedPaymentsTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ShareholdersEquityAndShareBasedPaymentsTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Shareholders' Equity and Share-based Payments [Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareholdersEquityAndShareBasedPaymentsTextBlock" xlink:to="us-gaap_ShareholdersEquityAndShareBasedPaymentsTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized</link:label>
    <link:label xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:to="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseExpense" xlink:label="us-gaap_OperatingLeaseExpense" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_OperatingLeaseExpense-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_OperatingLeaseExpense</link:label>
    <link:label xlink:label="us-gaap_OperatingLeaseExpense-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating Lease, Expense</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeaseExpense" xlink:to="us-gaap_OperatingLeaseExpense-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1</link:label>
    <link:label xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:to="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets by Major Class [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets, Major Class Name [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Award Type [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="us-gaap_AwardTypeAxis" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AwardTypeAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Award Type [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AwardTypeAxis" xlink:to="us-gaap_AwardTypeAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="us-gaap_NetIncomeLoss" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_NetIncomeLoss-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net income</link:label>
    <link:label xlink:label="us-gaap_NetIncomeLoss-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net income</link:label>
    <link:label xlink:label="us-gaap_NetIncomeLoss-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Consolidated net income</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetIncomeLoss" xlink:to="us-gaap_NetIncomeLoss-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization</link:label>
    <link:label xlink:label="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization-label" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Accumulated Amortization</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="us-gaap_FiniteLivedIntangibleAssetsNet" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_FiniteLivedIntangibleAssetsNet-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Definite-lived intangible assets, net</link:label>
    <link:label xlink:label="us-gaap_FiniteLivedIntangibleAssetsNet-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total</link:label>
    <link:label xlink:label="us-gaap_FiniteLivedIntangibleAssetsNet-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net Carrying Amount</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsNet" xlink:to="us-gaap_FiniteLivedIntangibleAssetsNet-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross" xlink:label="us-gaap_FiniteLivedIntangibleAssetsGross" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_FiniteLivedIntangibleAssetsGross-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_FiniteLivedIntangibleAssetsGross</link:label>
    <link:label xlink:label="us-gaap_FiniteLivedIntangibleAssetsGross-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Gross Carrying Amount</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsGross" xlink:to="us-gaap_FiniteLivedIntangibleAssetsGross-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestrictedStockMember" xlink:label="us-gaap_RestrictedStockMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_RestrictedStockMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Restricted Stock [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RestrictedStockMember" xlink:to="us-gaap_RestrictedStockMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="us-gaap_EmployeeStockOptionMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_EmployeeStockOptionMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Payment Arrangement, Option [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EmployeeStockOptionMember" xlink:to="us-gaap_EmployeeStockOptionMember-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_InternationalMember" xlink:label="apt_InternationalMember" xlink:type="locator"/>
    <link:label xlink:label="apt_InternationalMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">International Member</link:label>
    <link:label xlink:label="apt_InternationalMember-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">International [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_InternationalMember" xlink:to="apt_InternationalMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Antidilutive Securities [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:to="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CapitalizedComputerSoftwareGross" xlink:label="us-gaap_CapitalizedComputerSoftwareGross" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_CapitalizedComputerSoftwareGross-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Software</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CapitalizedComputerSoftwareGross" xlink:to="us-gaap_CapitalizedComputerSoftwareGross-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="us-gaap_AntidilutiveSecuritiesNameDomain" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AntidilutiveSecuritiesNameDomain-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Antidilutive Securities, Name [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AntidilutiveSecuritiesNameDomain" xlink:to="us-gaap_AntidilutiveSecuritiesNameDomain-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_The2004PlanMember" xlink:label="apt_The2004PlanMember" xlink:type="locator"/>
    <link:label xlink:label="apt_The2004PlanMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">The2004 Plan Member</link:label>
    <link:label xlink:label="apt_The2004PlanMember-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The 2004 Plan [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_The2004PlanMember" xlink:to="apt_The2004PlanMember-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_StockOptionsFairValueBasedOnBlackScholesMerton" xlink:label="apt_StockOptionsFairValueBasedOnBlackScholesMerton" xlink:type="locator"/>
    <link:label xlink:label="apt_StockOptionsFairValueBasedOnBlackScholesMerton-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Black-Scholes fair value (in dollars per share)</link:label>
    <link:label xlink:label="apt_StockOptionsFairValueBasedOnBlackScholesMerton-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Black-Scholes-Merton fair value (in Dollars per share)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_StockOptionsFairValueBasedOnBlackScholesMerton" xlink:to="apt_StockOptionsFairValueBasedOnBlackScholesMerton-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommitmentsAndContingenciesDisclosureTextBlock" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Commitments and Contingencies Disclosure [Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommitmentsAndContingenciesDisclosureTextBlock" xlink:to="us-gaap_CommitmentsAndContingenciesDisclosureTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_TemporaryDifferencesAbstract" xlink:label="apt_TemporaryDifferencesAbstract" xlink:type="locator"/>
    <link:label xlink:label="apt_TemporaryDifferencesAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Temporary differences:</link:label>
    <link:label xlink:label="apt_TemporaryDifferencesAbstract-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Temporary differences: [Abstract]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_TemporaryDifferencesAbstract" xlink:to="apt_TemporaryDifferencesAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment</link:label>
    <link:label xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment-label" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Less accumulated depreciation and amortization</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:to="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="us-gaap_PropertyPlantAndEquipmentNet" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PropertyPlantAndEquipmentNet-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property and equipment, net</link:label>
    <link:label xlink:label="us-gaap_PropertyPlantAndEquipmentNet-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total net property and equipment</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentNet" xlink:to="us-gaap_PropertyPlantAndEquipmentNet-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Goodwill" xlink:label="us-gaap_Goodwill" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_Goodwill-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Goodwill</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_Goodwill" xlink:to="us-gaap_Goodwill-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_DeferredTaxLiabilitiesStateIncomeTaxesNonCurrent" xlink:label="apt_DeferredTaxLiabilitiesStateIncomeTaxesNonCurrent" xlink:type="locator"/>
    <link:label xlink:label="apt_DeferredTaxLiabilitiesStateIncomeTaxesNonCurrent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">apt_DeferredTaxLiabilitiesStateIncomeTaxesNonCurrent</link:label>
    <link:label xlink:label="apt_DeferredTaxLiabilitiesStateIncomeTaxesNonCurrent-label" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">State income taxes</link:label>
    <link:label xlink:label="apt_DeferredTaxLiabilitiesStateIncomeTaxesNonCurrent-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Gross amount of noncurrent deferred tax liabilities, which result from applying the applicable tax rate to taxable temporary differences pertaining to each jurisdiction to which the entity is obligated to pay income tax.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_DeferredTaxLiabilitiesStateIncomeTaxesNonCurrent" xlink:to="apt_DeferredTaxLiabilitiesStateIncomeTaxesNonCurrent-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="us-gaap_PropertyPlantAndEquipmentGross" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PropertyPlantAndEquipmentGross-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_PropertyPlantAndEquipmentGross</link:label>
    <link:label xlink:label="us-gaap_PropertyPlantAndEquipmentGross-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment, Gross, Ending Balance</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentGross" xlink:to="us-gaap_PropertyPlantAndEquipmentGross-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MachineryAndEquipmentGross" xlink:label="us-gaap_MachineryAndEquipmentGross" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_MachineryAndEquipmentGross-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Machinery and equipment</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MachineryAndEquipmentGross" xlink:to="us-gaap_MachineryAndEquipmentGross-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FurnitureAndFixturesGross" xlink:label="us-gaap_FurnitureAndFixturesGross" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_FurnitureAndFixturesGross-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Office furniture and equipment</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FurnitureAndFixturesGross" xlink:to="us-gaap_FurnitureAndFixturesGross-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LeaseholdImprovementsGross" xlink:label="us-gaap_LeaseholdImprovementsGross" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_LeaseholdImprovementsGross-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Leasehold improvements</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LeaseholdImprovementsGross" xlink:to="us-gaap_LeaseholdImprovementsGross-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_HarmonyMember" xlink:label="apt_HarmonyMember" xlink:type="locator"/>
    <link:label xlink:label="apt_HarmonyMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Harmony [Member]</link:label>
    <link:label xlink:label="apt_HarmonyMember-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Information by name of investment.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_HarmonyMember" xlink:to="apt_HarmonyMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BuildingsAndImprovementsGross" xlink:label="us-gaap_BuildingsAndImprovementsGross" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_BuildingsAndImprovementsGross-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Buildings</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BuildingsAndImprovementsGross" xlink:to="us-gaap_BuildingsAndImprovementsGross-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_EmployeesAndDirectorsMember" xlink:label="apt_EmployeesAndDirectorsMember" xlink:type="locator"/>
    <link:label xlink:label="apt_EmployeesAndDirectorsMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Employees and Directors [Member]</link:label>
    <link:label xlink:label="apt_EmployeesAndDirectorsMember-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">To whom the options outstanding are granted to.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_EmployeesAndDirectorsMember" xlink:to="apt_EmployeesAndDirectorsMember-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_DeferredTaxAssetsTaxCreditCarryforwardsAlternativeMinimumTaxAndForeignTaxCredits" xlink:label="apt_DeferredTaxAssetsTaxCreditCarryforwardsAlternativeMinimumTaxAndForeignTaxCredits" xlink:type="locator"/>
    <link:label xlink:label="apt_DeferredTaxAssetsTaxCreditCarryforwardsAlternativeMinimumTaxAndForeignTaxCredits-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">AMT/Foreign tax credits</link:label>
    <link:label xlink:label="apt_DeferredTaxAssetsTaxCreditCarryforwardsAlternativeMinimumTaxAndForeignTaxCredits-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Amount before allocation of valuation allowances of deferred tax asset attributable to deductible alternative minimum tax and foreign tax credit carryforwards.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_DeferredTaxAssetsTaxCreditCarryforwardsAlternativeMinimumTaxAndForeignTaxCredits" xlink:to="apt_DeferredTaxAssetsTaxCreditCarryforwardsAlternativeMinimumTaxAndForeignTaxCredits-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:label="us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_EquityMethodInvestmentOwnershipPercentage-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_EquityMethodInvestmentOwnershipPercentage</link:label>
    <link:label xlink:label="us-gaap_EquityMethodInvestmentOwnershipPercentage-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Equity Method Investment, Ownership Percentage</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:to="us-gaap_EquityMethodInvestmentOwnershipPercentage-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_DeferredCompensationArrangementWithIndividualRecordedLiabilityCurrent" xlink:label="apt_DeferredCompensationArrangementWithIndividualRecordedLiabilityCurrent" xlink:type="locator"/>
    <link:label xlink:label="apt_DeferredCompensationArrangementWithIndividualRecordedLiabilityCurrent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">apt_DeferredCompensationArrangementWithIndividualRecordedLiabilityCurrent</link:label>
    <link:label xlink:label="apt_DeferredCompensationArrangementWithIndividualRecordedLiabilityCurrent-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Deferred Compensation Arrangement With Individual Recorded Liability Current</link:label>
    <link:label xlink:label="apt_DeferredCompensationArrangementWithIndividualRecordedLiabilityCurrent-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The compensation expense recognized during the current period pertaining to the deferred compensation arrangement.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_DeferredCompensationArrangementWithIndividualRecordedLiabilityCurrent" xlink:to="apt_DeferredCompensationArrangementWithIndividualRecordedLiabilityCurrent-label" xlink:type="arc"/>
    <link:loc xlink:href="https://xbrl.sec.gov/country/2020/country-2020-01-31.xsd#country_AU" xlink:label="country_AU" xlink:type="locator"/>
    <link:label xlink:label="country_AU-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">AUSTRALIA</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="country_AU" xlink:to="country_AU-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash Flows From Investing Activities:</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EarningsPerShareAbstract" xlink:label="us-gaap_EarningsPerShareAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_EarningsPerShareAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Earnings per common share:</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EarningsPerShareAbstract" xlink:to="us-gaap_EarningsPerShareAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" xlink:label="us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity investment in unconsolidated affiliate</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" xlink:to="us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestments" xlink:label="us-gaap_IncomeLossFromEquityMethodInvestments" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IncomeLossFromEquityMethodInvestments-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity in income of unconsolidated affiliate</link:label>
    <link:label xlink:label="us-gaap_IncomeLossFromEquityMethodInvestments-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Income (Loss) from Equity Method Investments, Total</link:label>
    <link:label xlink:label="us-gaap_IncomeLossFromEquityMethodInvestments-label" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Equity in income of unconsolidated affiliate</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeLossFromEquityMethodInvestments" xlink:to="us-gaap_IncomeLossFromEquityMethodInvestments-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:label="us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities</link:label>
    <link:label xlink:label="us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accounts payable and accrued liabilities</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:to="us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityMethodInvestments" xlink:label="us-gaap_EquityMethodInvestments" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_EquityMethodInvestments-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_EquityMethodInvestments</link:label>
    <link:label xlink:label="us-gaap_EquityMethodInvestments-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Equity Method Investments</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EquityMethodInvestments" xlink:to="us-gaap_EquityMethodInvestments-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionsDisclosureTextBlock" xlink:label="us-gaap_RelatedPartyTransactionsDisclosureTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_RelatedPartyTransactionsDisclosureTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party Transactions Disclosure [Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RelatedPartyTransactionsDisclosureTextBlock" xlink:to="us-gaap_RelatedPartyTransactionsDisclosureTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="us-gaap_IncomeTaxExpenseBenefit" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IncomeTaxExpenseBenefit-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Provision for income taxes</link:label>
    <link:label xlink:label="us-gaap_IncomeTaxExpenseBenefit-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Provision for income taxes</link:label>
    <link:label xlink:label="us-gaap_IncomeTaxExpenseBenefit-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Provision for income taxes</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxExpenseBenefit" xlink:to="us-gaap_IncomeTaxExpenseBenefit-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_RevenueFromContractWithCustomerShippingAndHandlingPolicyPolicyTextBlock" xlink:label="apt_RevenueFromContractWithCustomerShippingAndHandlingPolicyPolicyTextBlock" xlink:type="locator"/>
    <link:label xlink:label="apt_RevenueFromContractWithCustomerShippingAndHandlingPolicyPolicyTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revenue from Contract with Customer, Shipping and Handling, Policy [Policy Text Block]</link:label>
    <link:label xlink:label="apt_RevenueFromContractWithCustomerShippingAndHandlingPolicyPolicyTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Disclosure of accounting policy for the classification of shipping and handling costs, including whether the costs are included in cost of sales or included in other income statement accounts. If shipping and handling fees are significant and are not included in cost of sales, disclosure includes both the amounts of such costs and the line item on the income statement which includes such costs.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_RevenueFromContractWithCustomerShippingAndHandlingPolicyPolicyTextBlock" xlink:to="apt_RevenueFromContractWithCustomerShippingAndHandlingPolicyPolicyTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_DeferredCompensationArrangementWithIndividualDeathBenefit" xlink:label="apt_DeferredCompensationArrangementWithIndividualDeathBenefit" xlink:type="locator"/>
    <link:label xlink:label="apt_DeferredCompensationArrangementWithIndividualDeathBenefit-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">apt_DeferredCompensationArrangementWithIndividualDeathBenefit</link:label>
    <link:label xlink:label="apt_DeferredCompensationArrangementWithIndividualDeathBenefit-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Deferred Compensation Arrangement with Individual, Death Benefit</link:label>
    <link:label xlink:label="apt_DeferredCompensationArrangementWithIndividualDeathBenefit-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the carrying amount of death benefits accrued.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_DeferredCompensationArrangementWithIndividualDeathBenefit" xlink:to="apt_DeferredCompensationArrangementWithIndividualDeathBenefit-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_ProceedsFromPaymentsForStockOptionsExercised" xlink:label="apt_ProceedsFromPaymentsForStockOptionsExercised" xlink:type="locator"/>
    <link:label xlink:label="apt_ProceedsFromPaymentsForStockOptionsExercised-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds from exercise of stock options</link:label>
    <link:label xlink:label="apt_ProceedsFromPaymentsForStockOptionsExercised-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The cash inflow from or (outflow of) cash for stock options exercised during the period.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_ProceedsFromPaymentsForStockOptionsExercised" xlink:to="apt_ProceedsFromPaymentsForStockOptionsExercised-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingExpenses" xlink:label="us-gaap_OperatingExpenses" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_OperatingExpenses-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_OperatingExpenses</link:label>
    <link:label xlink:label="us-gaap_OperatingExpenses-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total operating expenses</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingExpenses" xlink:to="us-gaap_OperatingExpenses-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount" xlink:label="us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount</link:label>
    <link:label xlink:label="us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Defined Contribution Plan, Employer Discretionary Contribution Amount</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount" xlink:to="us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent" xlink:label="us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent</link:label>
    <link:label xlink:label="us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent" xlink:to="us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent" xlink:label="us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent</link:label>
    <link:label xlink:label="us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent" xlink:to="us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash and cash equivalents</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:to="us-gaap_CashAndCashEquivalentsAtCarryingValue-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="us-gaap_AllocatedShareBasedCompensationExpense" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AllocatedShareBasedCompensationExpense-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_AllocatedShareBasedCompensationExpense</link:label>
    <link:label xlink:label="us-gaap_AllocatedShareBasedCompensationExpense-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based Payment Arrangement, Expense</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AllocatedShareBasedCompensationExpense" xlink:to="us-gaap_AllocatedShareBasedCompensationExpense-label" xlink:type="arc"/>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_AmendmentFlag" xlink:label="dei_AmendmentFlag" xlink:type="locator"/>
    <link:label xlink:label="dei_AmendmentFlag-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Amendment Flag</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_AmendmentFlag" xlink:to="dei_AmendmentFlag-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_UseOfEstimates" xlink:label="us-gaap_UseOfEstimates" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_UseOfEstimates-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Use of Estimates, Policy [Policy Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_UseOfEstimates" xlink:to="us-gaap_UseOfEstimates-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:label="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">New Accounting Pronouncements, Policy [Policy Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:to="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="https://xbrl.sec.gov/country/2020/country-2020-01-31.xsd#country_IN" xlink:label="country_IN" xlink:type="locator"/>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInContractWithCustomerLiability" xlink:label="us-gaap_IncreaseDecreaseInContractWithCustomerLiability" xlink:type="locator"/>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInContractWithCustomerLiability" xlink:to="us-gaap_IncreaseDecreaseInContractWithCustomerLiability-label" xlink:type="arc"/>
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    <link:label xlink:label="dei_CurrentFiscalYearEndDate-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Current Fiscal Year End Date</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent" xlink:to="us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent-label" xlink:type="arc"/>
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    <link:label xlink:label="dei_DocumentFiscalPeriodFocus-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Document Fiscal Period Focus</link:label>
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    <link:label xlink:label="us-gaap_ConsolidationPolicyTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Consolidation, Policy [Policy Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConsolidationPolicyTextBlock" xlink:to="us-gaap_ConsolidationPolicyTextBlock-label" xlink:type="arc"/>
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    <link:label xlink:label="dei_DocumentPeriodEndDate-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Document Period End Date</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1" xlink:to="us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1-label" xlink:type="arc"/>
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    <link:label xlink:label="us-gaap_IncreaseDecreaseInPrepaidExpense-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_IncreaseDecreaseInPrepaidExpense</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInPrepaidExpense" xlink:to="us-gaap_IncreaseDecreaseInPrepaidExpense-label" xlink:type="arc"/>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityEmergingGrowthCompany" xlink:label="dei_EntityEmergingGrowthCompany" xlink:type="locator"/>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityEmergingGrowthCompany" xlink:to="dei_EntityEmergingGrowthCompany-label" xlink:type="arc"/>
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    <link:label xlink:label="dei_DocumentType-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Document Type</link:label>
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    <link:label xlink:label="us-gaap_AssetImpairmentCharges-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Asset Impairment Charges, Total</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AssetImpairmentCharges" xlink:to="us-gaap_AssetImpairmentCharges-label" xlink:type="arc"/>
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    <link:label xlink:label="dei_EntitySmallBusiness-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Small Business</link:label>
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    <link:label xlink:label="dei_EntityShellCompany-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Shell Company</link:label>
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    <link:label xlink:label="dei_DocumentInformationLineItems-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Document Information [Line Items]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_DocumentInformationLineItems-label" xlink:type="arc"/>
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    <link:label xlink:label="dei_DocumentInformationTable-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Document Information [Table]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_DocumentInformationTable" xlink:to="dei_DocumentInformationTable-label" xlink:type="arc"/>
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    <link:label xlink:label="us-gaap_VariableRateAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Variable Rate [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_VariableRateAxis" xlink:to="us-gaap_VariableRateAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:label="us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IncreaseDecreaseInAccountsReceivable-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_IncreaseDecreaseInAccountsReceivable</link:label>
    <link:label xlink:label="us-gaap_IncreaseDecreaseInAccountsReceivable-label" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Accounts receivable, net</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:to="us-gaap_IncreaseDecreaseInAccountsReceivable-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:label="us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based compensation expense</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:to="us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskPercentage1" xlink:label="us-gaap_ConcentrationRiskPercentage1" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ConcentrationRiskPercentage1-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Customer</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConcentrationRiskPercentage1" xlink:to="us-gaap_ConcentrationRiskPercentage1-label" xlink:type="arc"/>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityCentralIndexKey" xlink:label="dei_EntityCentralIndexKey" xlink:type="locator"/>
    <link:label xlink:label="dei_EntityCentralIndexKey-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Central Index Key</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityCentralIndexKey" xlink:to="dei_EntityCentralIndexKey-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DepreciationAndAmortization" xlink:label="us-gaap_DepreciationAndAmortization" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DepreciationAndAmortization-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_DepreciationAndAmortization</link:label>
    <link:label xlink:label="us-gaap_DepreciationAndAmortization-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Depreciation, Depletion and Amortization, Nonproduction, Total</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DepreciationAndAmortization" xlink:to="us-gaap_DepreciationAndAmortization-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_ForEmployeesContributing2To12PercentOfGrossEarningsMember" xlink:label="apt_ForEmployeesContributing2To12PercentOfGrossEarningsMember" xlink:type="locator"/>
    <link:label xlink:label="apt_ForEmployeesContributing2To12PercentOfGrossEarningsMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">For Employees Contributing 2 to12 Percent of Gross Earnings [Member]</link:label>
    <link:label xlink:label="apt_ForEmployeesContributing2To12PercentOfGrossEarningsMember-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents employees who contribute between 2% to 12% of their gross earnings.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_ForEmployeesContributing2To12PercentOfGrossEarningsMember" xlink:to="apt_ForEmployeesContributing2To12PercentOfGrossEarningsMember-label" xlink:type="arc"/>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityRegistrantName" xlink:label="dei_EntityRegistrantName" xlink:type="locator"/>
    <link:label xlink:label="dei_EntityRegistrantName-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Registrant Name</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityRegistrantName" xlink:to="dei_EntityRegistrantName-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_ForEmployeesContributing1PercentOfGrossEarningsMember" xlink:label="apt_ForEmployeesContributing1PercentOfGrossEarningsMember" xlink:type="locator"/>
    <link:label xlink:label="apt_ForEmployeesContributing1PercentOfGrossEarningsMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">For Employees Contributing 1 Percent of Gross Earnings [Member]</link:label>
    <link:label xlink:label="apt_ForEmployeesContributing1PercentOfGrossEarningsMember-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents employees contributing 1% of gross earnings.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_ForEmployeesContributing1PercentOfGrossEarningsMember" xlink:to="apt_ForEmployeesContributing1PercentOfGrossEarningsMember-label" xlink:type="arc"/>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityDomain" xlink:label="dei_EntityDomain" xlink:type="locator"/>
    <link:label xlink:label="dei_EntityDomain-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityDomain" xlink:to="dei_EntityDomain-label" xlink:type="arc"/>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_LegalEntityAxis" xlink:label="dei_LegalEntityAxis" xlink:type="locator"/>
    <link:label xlink:label="dei_LegalEntityAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Legal Entity [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_LegalEntityAxis" xlink:to="dei_LegalEntityAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CustomerConcentrationRiskMember" xlink:label="us-gaap_CustomerConcentrationRiskMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_CustomerConcentrationRiskMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Customer Concentration Risk [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CustomerConcentrationRiskMember" xlink:to="us-gaap_CustomerConcentrationRiskMember-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_CustomerBMember" xlink:label="apt_CustomerBMember" xlink:type="locator"/>
    <link:label xlink:label="apt_CustomerBMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Customer B [Member]</link:label>
    <link:label xlink:label="apt_CustomerBMember-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents a major customer.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_CustomerBMember" xlink:to="apt_CustomerBMember-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_CustomerAMember" xlink:label="apt_CustomerAMember" xlink:type="locator"/>
    <link:label xlink:label="apt_CustomerAMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Customer A [Member]</link:label>
    <link:label xlink:label="apt_CustomerAMember-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents major customer.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_CustomerAMember" xlink:to="apt_CustomerAMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:label="us-gaap_AmortizationOfIntangibleAssets" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AmortizationOfIntangibleAssets-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_AmortizationOfIntangibleAssets</link:label>
    <link:label xlink:label="us-gaap_AmortizationOfIntangibleAssets-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amortization of Intangible Assets, Total</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AmortizationOfIntangibleAssets" xlink:to="us-gaap_AmortizationOfIntangibleAssets-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInDueFromRelatedParties" xlink:label="us-gaap_IncreaseDecreaseInDueFromRelatedParties" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IncreaseDecreaseInDueFromRelatedParties-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_IncreaseDecreaseInDueFromRelatedParties</link:label>
    <link:label xlink:label="us-gaap_IncreaseDecreaseInDueFromRelatedParties-label" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Accounts receivable, related party</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInDueFromRelatedParties" xlink:to="us-gaap_IncreaseDecreaseInDueFromRelatedParties-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_CustomerCMember" xlink:label="apt_CustomerCMember" xlink:type="locator"/>
    <link:label xlink:label="apt_CustomerCMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Customer C [Member]</link:label>
    <link:label xlink:label="apt_CustomerCMember-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents a major customer.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_CustomerCMember" xlink:to="apt_CustomerCMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis" xlink:label="us-gaap_ConcentrationRiskByTypeAxis" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ConcentrationRiskByTypeAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk Type [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConcentrationRiskByTypeAxis" xlink:to="us-gaap_ConcentrationRiskByTypeAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="us-gaap_ConcentrationRiskTypeDomain" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ConcentrationRiskTypeDomain-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk Type [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConcentrationRiskTypeDomain" xlink:to="us-gaap_ConcentrationRiskTypeDomain-label" xlink:type="arc"/>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityCommonStockSharesOutstanding" xlink:label="dei_EntityCommonStockSharesOutstanding" xlink:type="locator"/>
    <link:label xlink:label="dei_EntityCommonStockSharesOutstanding-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Common Stock, Shares Outstanding (in shares)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityCommonStockSharesOutstanding" xlink:to="dei_EntityCommonStockSharesOutstanding-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodValue" xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodValue" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodValue-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_StockRepurchasedAndRetiredDuringPeriodValue</link:label>
    <link:label xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodValue-label" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Common stock repurchased and retired</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockRepurchasedAndRetiredDuringPeriodValue" xlink:to="us-gaap_StockRepurchasedAndRetiredDuringPeriodValue-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InvestmentsInDebtAndMarketableEquitySecuritiesAndCertainTradingAssetsDisclosureTextBlock" xlink:label="us-gaap_InvestmentsInDebtAndMarketableEquitySecuritiesAndCertainTradingAssetsDisclosureTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_InvestmentsInDebtAndMarketableEquitySecuritiesAndCertainTradingAssetsDisclosureTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InvestmentsInDebtAndMarketableEquitySecuritiesAndCertainTradingAssetsDisclosureTextBlock" xlink:to="us-gaap_InvestmentsInDebtAndMarketableEquitySecuritiesAndCertainTradingAssetsDisclosureTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_StockRepurchasedAndRetiredDuringPeriodShares</link:label>
    <link:label xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Stock Repurchased and Retired During Period, Shares (in shares)</link:label>
    <link:label xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares-label" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Common stock repurchased and retired (in shares)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" xlink:to="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdvertisingExpense" xlink:label="us-gaap_AdvertisingExpense" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AdvertisingExpense-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_AdvertisingExpense</link:label>
    <link:label xlink:label="us-gaap_AdvertisingExpense-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Advertising Expense</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AdvertisingExpense" xlink:to="us-gaap_AdvertisingExpense-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SalesRevenueNetMember" xlink:label="us-gaap_SalesRevenueNetMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_SalesRevenueNetMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revenue Benchmark [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SalesRevenueNetMember" xlink:to="us-gaap_SalesRevenueNetMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsReceivableMember" xlink:label="us-gaap_AccountsReceivableMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AccountsReceivableMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounts Receivable [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccountsReceivableMember" xlink:to="us-gaap_AccountsReceivableMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember" xlink:label="us-gaap_InvestmentTypeCategorizationMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_InvestmentTypeCategorizationMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Investments [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InvestmentTypeCategorizationMember" xlink:to="us-gaap_InvestmentTypeCategorizationMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInInventories" xlink:label="us-gaap_IncreaseDecreaseInInventories" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IncreaseDecreaseInInventories-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_IncreaseDecreaseInInventories</link:label>
    <link:label xlink:label="us-gaap_IncreaseDecreaseInInventories-label" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Inventories</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInInventories" xlink:to="us-gaap_IncreaseDecreaseInInventories-label" xlink:type="arc"/>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_TradingSymbol" xlink:label="dei_TradingSymbol" xlink:type="locator"/>
    <link:label xlink:label="dei_TradingSymbol-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Trading Symbol</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_TradingSymbol" xlink:to="dei_TradingSymbol-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:label="us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ConcentrationRiskByBenchmarkAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk Benchmark [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:to="us-gaap_ConcentrationRiskByBenchmarkAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="us-gaap_ConcentrationRiskBenchmarkDomain" xlink:type="locator"/>
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    <link:label xlink:label="us-gaap_InvestmentTypeAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Investment Type [Axis]</link:label>
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    <link:label xlink:label="us-gaap_NatureOfOperations-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Nature of Operations [Text Block]</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TableTextBlock" xlink:label="us-gaap_TableTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_TableTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_TableTextBlock</link:label>
    <link:label xlink:label="us-gaap_TableTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Notes Tables</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TableTextBlock" xlink:to="us-gaap_TableTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity</link:label>
    <link:label xlink:label="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Line of Credit Facility, Maximum Borrowing Capacity</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:to="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" xlink:label="us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Options exercised</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" xlink:to="us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpense" xlink:label="us-gaap_SellingGeneralAndAdministrativeExpense" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_SellingGeneralAndAdministrativeExpense-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Selling, general and administrative</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SellingGeneralAndAdministrativeExpense" xlink:to="us-gaap_SellingGeneralAndAdministrativeExpense-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Granted to employees and directors (in shares)</link:label>
    <link:label xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InventoryRawMaterialsNetOfReserves" xlink:label="us-gaap_InventoryRawMaterialsNetOfReserves" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_InventoryRawMaterialsNetOfReserves-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Raw materials</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InventoryRawMaterialsNetOfReserves" xlink:to="us-gaap_InventoryRawMaterialsNetOfReserves-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_LiabilitiesAndStockholdersEquity-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_LiabilitiesAndStockholdersEquity</link:label>
    <link:label xlink:label="us-gaap_LiabilitiesAndStockholdersEquity-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total liabilities and shareholders' equity</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="us-gaap_LiabilitiesAndStockholdersEquity-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InventoryFinishedGoodsNetOfReserves" xlink:label="us-gaap_InventoryFinishedGoodsNetOfReserves" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_InventoryFinishedGoodsNetOfReserves-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finished goods</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InventoryFinishedGoodsNetOfReserves" xlink:to="us-gaap_InventoryFinishedGoodsNetOfReserves-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InventoryWorkInProcessNetOfReserves" xlink:label="us-gaap_InventoryWorkInProcessNetOfReserves" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_InventoryWorkInProcessNetOfReserves-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Work in process</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InventoryWorkInProcessNetOfReserves" xlink:to="us-gaap_InventoryWorkInProcessNetOfReserves-label" xlink:type="arc"/>
    <link:loc xlink:href="https://xbrl.sec.gov/country/2020/country-2020-01-31.xsd#country_US" xlink:label="country_US" xlink:type="locator"/>
    <link:label xlink:label="country_US-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">UNITED STATES</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="country_US" xlink:to="country_US-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit" xlink:type="locator"/>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RetainedEarningsAccumulatedDeficit" xlink:to="us-gaap_RetainedEarningsAccumulatedDeficit-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtDisclosureTextBlock" xlink:label="us-gaap_DebtDisclosureTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DebtDisclosureTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Disclosure [Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtDisclosureTextBlock" xlink:to="us-gaap_DebtDisclosureTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:label="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Changes in assets and liabilities:</link:label>
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    <link:label xlink:label="us-gaap_DisclosureTextBlockAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_DisclosureTextBlockAbstract</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:to="us-gaap_OperatingLeaseLiabilityNoncurrent-label" xlink:type="arc"/>
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    <link:label xlink:label="us-gaap_ScheduleOfInventoryCurrentTableTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Inventory, Current [Table Text Block]</link:label>
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    <link:label xlink:label="us-gaap_OperatingLeaseLiability-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Total lease liabilities</link:label>
    <link:label xlink:label="us-gaap_OperatingLeaseLiability-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating Lease, Liability, Total</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeaseLiability" xlink:to="us-gaap_OperatingLeaseLiability-label" xlink:type="arc"/>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeaseLiabilityCurrent" xlink:to="us-gaap_OperatingLeaseLiabilityCurrent-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock" xlink:label="us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Retirement Benefits [Text Block]</link:label>
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    <link:loc xlink:href="apt-20201231.xsd#apt_OperatingLeaseRightofuseAssetNoncurrent" xlink:label="apt_OperatingLeaseRightofuseAssetNoncurrent" xlink:type="locator"/>
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    <link:label xlink:label="apt_OperatingLeaseRightofuseAssetNoncurrent-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Amount of lessee's right to use underlying asset under operating lease, net of current portion.</link:label>
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    <link:label xlink:label="us-gaap_SubsequentEventsTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Subsequent Events [Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SubsequentEventsTextBlock" xlink:to="us-gaap_SubsequentEventsTextBlock-label" xlink:type="arc"/>
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    <link:label xlink:label="us-gaap_OperatingLeaseRightOfUseAsset-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_OperatingLeaseRightOfUseAsset</link:label>
    <link:label xlink:label="us-gaap_OperatingLeaseRightOfUseAsset-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating Lease, Right-of-Use Asset</link:label>
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    <link:label xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue</link:label>
    <link:label xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total future minimum lease payments</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinanceLeaseLiability" xlink:label="us-gaap_FinanceLeaseLiability" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_FinanceLeaseLiability-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_FinanceLeaseLiability</link:label>
    <link:label xlink:label="us-gaap_FinanceLeaseLiability-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Finance Lease, Liability, Total</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinanceLeaseLiability" xlink:to="us-gaap_FinanceLeaseLiability-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_OperatingLeaseExpenseNetOfAccretion" xlink:label="apt_OperatingLeaseExpenseNetOfAccretion" xlink:type="locator"/>
    <link:label xlink:label="apt_OperatingLeaseExpenseNetOfAccretion-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating lease expense, net of accretion</link:label>
    <link:label xlink:label="apt_OperatingLeaseExpenseNetOfAccretion-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the amount of operating lease expense, net of accretion during the period.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_OperatingLeaseExpenseNetOfAccretion" xlink:to="apt_OperatingLeaseExpenseNetOfAccretion-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount</link:label>
    <link:label xlink:label="us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount-label" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Less imputed interest</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:label="us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DeferredIncomeTaxExpenseBenefit-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred income taxes</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:to="us-gaap_DeferredIncomeTaxExpenseBenefit-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_IncreaseDecreaseInOperatingLeaseLiability" xlink:label="apt_IncreaseDecreaseInOperatingLeaseLiability" xlink:type="locator"/>
    <link:label xlink:label="apt_IncreaseDecreaseInOperatingLeaseLiability-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">apt_IncreaseDecreaseInOperatingLeaseLiability</link:label>
    <link:label xlink:label="apt_IncreaseDecreaseInOperatingLeaseLiability-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lease liabilities</link:label>
    <link:label xlink:label="apt_IncreaseDecreaseInOperatingLeaseLiability-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The increase (decrease) during the reporting period operating lease liabilities.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_IncreaseDecreaseInOperatingLeaseLiability" xlink:to="apt_IncreaseDecreaseInOperatingLeaseLiability-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2023</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2024</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2025</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementPolicyPolicyTextBlock" xlink:label="us-gaap_FairValueMeasurementPolicyPolicyTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_FairValueMeasurementPolicyPolicyTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value Measurement, Policy [Policy Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueMeasurementPolicyPolicyTextBlock" xlink:to="us-gaap_FairValueMeasurementPolicyPolicyTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo</link:label>
    <link:label xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2022</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueOfFinancialInstrumentsPolicy" xlink:label="us-gaap_FairValueOfFinancialInstrumentsPolicy" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_FairValueOfFinancialInstrumentsPolicy-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value of Financial Instruments, Policy [Policy Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueOfFinancialInstrumentsPolicy" xlink:to="us-gaap_FairValueOfFinancialInstrumentsPolicy-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree</link:label>
    <link:label xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2023</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour</link:label>
    <link:label xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2024</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2021</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2022</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_BonusPercentage" xlink:label="apt_BonusPercentage" xlink:type="locator"/>
    <link:label xlink:label="apt_BonusPercentage-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">apt_BonusPercentage</link:label>
    <link:label xlink:label="apt_BonusPercentage-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Bonus Percentage</link:label>
    <link:label xlink:label="apt_BonusPercentage-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The bonus paid to the CEO and President in percentage of the Company's pre-tax profits.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_BonusPercentage" xlink:to="apt_BonusPercentage-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredCompensationArrangementWithIndividualRecordedLiability" xlink:label="us-gaap_DeferredCompensationArrangementWithIndividualRecordedLiability" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DeferredCompensationArrangementWithIndividualRecordedLiability-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_DeferredCompensationArrangementWithIndividualRecordedLiability</link:label>
    <link:label xlink:label="us-gaap_DeferredCompensationArrangementWithIndividualRecordedLiability-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Deferred Compensation Arrangement with Individual, Recorded Liability</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredCompensationArrangementWithIndividualRecordedLiability" xlink:to="us-gaap_DeferredCompensationArrangementWithIndividualRecordedLiability-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock" xlink:label="us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock" xlink:to="us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths</link:label>
    <link:label xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2021</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IssuanceOfStockAndWarrantsForServicesOrClaims" xlink:label="us-gaap_IssuanceOfStockAndWarrantsForServicesOrClaims" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IssuanceOfStockAndWarrantsForServicesOrClaims-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Basis difference in investments</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IssuanceOfStockAndWarrantsForServicesOrClaims" xlink:to="us-gaap_IssuanceOfStockAndWarrantsForServicesOrClaims-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ForeignCurrencyTransactionsAndTranslationsPolicyTextBlock" xlink:label="us-gaap_ForeignCurrencyTransactionsAndTranslationsPolicyTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ForeignCurrencyTransactionsAndTranslationsPolicyTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Foreign Currency Transactions and Translations Policy [Policy Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ForeignCurrencyTransactionsAndTranslationsPolicyTextBlock" xlink:to="us-gaap_ForeignCurrencyTransactionsAndTranslationsPolicyTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessee, Operating Lease, Liability, Maturity [Table Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="us-gaap_ShareBasedCompensation" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ShareBasedCompensation-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based compensation</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensation" xlink:to="us-gaap_ShareBasedCompensation-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife" xlink:label="us-gaap_FiniteLivedIntangibleAssetUsefulLife" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_FiniteLivedIntangibleAssetUsefulLife-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Weighted Average Amortization Period (Year)</link:label>
    <link:label xlink:label="us-gaap_FiniteLivedIntangibleAssetUsefulLife-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Asset, Useful Life (Year)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetUsefulLife" xlink:to="us-gaap_FiniteLivedIntangibleAssetUsefulLife-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EarningsPerSharePolicyTextBlock" xlink:label="us-gaap_EarningsPerSharePolicyTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_EarningsPerSharePolicyTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Earnings Per Share, Policy [Policy Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EarningsPerSharePolicyTextBlock" xlink:to="us-gaap_EarningsPerSharePolicyTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Revenues" xlink:label="us-gaap_Revenues" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_Revenues-label" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Consolidated sales</link:label>
    <link:label xlink:label="us-gaap_Revenues-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_Revenues</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_Revenues" xlink:to="us-gaap_Revenues-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingExpensesAbstract" xlink:label="us-gaap_OperatingExpensesAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_OperatingExpensesAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating expenses:</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingExpensesAbstract" xlink:to="us-gaap_OperatingExpensesAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxPolicyTextBlock" xlink:label="us-gaap_IncomeTaxPolicyTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IncomeTaxPolicyTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Tax, Policy [Policy Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxPolicyTextBlock" xlink:to="us-gaap_IncomeTaxPolicyTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock" xlink:label="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Finite-Lived Intangible Assets [Table Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock" xlink:to="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ResearchAndDevelopmentExpensePolicy" xlink:label="us-gaap_ResearchAndDevelopmentExpensePolicy" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ResearchAndDevelopmentExpensePolicy-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Research and Development Expense, Policy [Policy Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ResearchAndDevelopmentExpensePolicy" xlink:to="us-gaap_ResearchAndDevelopmentExpensePolicy-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_ConcentrationRiskThresholdPercentage" xlink:label="apt_ConcentrationRiskThresholdPercentage" xlink:type="locator"/>
    <link:label xlink:label="apt_ConcentrationRiskThresholdPercentage-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">apt_ConcentrationRiskThresholdPercentage</link:label>
    <link:label xlink:label="apt_ConcentrationRiskThresholdPercentage-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Concentration Risk Threshold Percentage</link:label>
    <link:label xlink:label="apt_ConcentrationRiskThresholdPercentage-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The concentration risk threshold percentage derived from quantitative amount.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_ConcentrationRiskThresholdPercentage" xlink:to="apt_ConcentrationRiskThresholdPercentage-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DepreciationDepletionAndAmortization" xlink:label="us-gaap_DepreciationDepletionAndAmortization" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DepreciationDepletionAndAmortization-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Depreciation and amortization</link:label>
    <link:label xlink:label="us-gaap_DepreciationDepletionAndAmortization-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Depreciation and amortization</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DepreciationDepletionAndAmortization" xlink:to="us-gaap_DepreciationDepletionAndAmortization-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="us-gaap_AssetsCurrent" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AssetsCurrent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_AssetsCurrent</link:label>
    <link:label xlink:label="us-gaap_AssetsCurrent-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total current assets</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AssetsCurrent" xlink:to="us-gaap_AssetsCurrent-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy" xlink:label="us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Payment Arrangement [Policy Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy" xlink:to="us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdvertisingCostsPolicyTextBlock" xlink:label="us-gaap_AdvertisingCostsPolicyTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AdvertisingCostsPolicyTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Advertising Cost [Policy Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AdvertisingCostsPolicyTextBlock" xlink:to="us-gaap_AdvertisingCostsPolicyTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestIncomeExpenseNonoperatingNet" xlink:label="us-gaap_InterestIncomeExpenseNonoperatingNet" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_InterestIncomeExpenseNonoperatingNet-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest income, net</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InterestIncomeExpenseNonoperatingNet" xlink:to="us-gaap_InterestIncomeExpenseNonoperatingNet-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockValue" xlink:label="us-gaap_CommonStockValue" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_CommonStockValue-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common stock, $.01 par value: 50,000,000 shares authorized; 13,419,847 and 12,885,273 shares outstanding as of December 31, 2020 and December 31, 2019, respectively</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockValue" xlink:to="us-gaap_CommonStockValue-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Adjustments to reconcile net income to net cash provided by operating activities:</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockSharesAuthorized" xlink:label="us-gaap_CommonStockSharesAuthorized" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_CommonStockSharesAuthorized-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common stock, shares authorized (in shares)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockSharesAuthorized" xlink:to="us-gaap_CommonStockSharesAuthorized-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockParOrStatedValuePerShare" xlink:label="us-gaap_CommonStockParOrStatedValuePerShare" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_CommonStockParOrStatedValuePerShare-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common stock, par value (in dollars per share)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockParOrStatedValuePerShare" xlink:to="us-gaap_CommonStockParOrStatedValuePerShare-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockCapitalSharesReservedForFutureIssuance" xlink:label="us-gaap_CommonStockCapitalSharesReservedForFutureIssuance" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_CommonStockCapitalSharesReservedForFutureIssuance-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_CommonStockCapitalSharesReservedForFutureIssuance</link:label>
    <link:label xlink:label="us-gaap_CommonStockCapitalSharesReservedForFutureIssuance-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Common Stock, Capital Shares Reserved for Future Issuance (in shares)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockCapitalSharesReservedForFutureIssuance" xlink:to="us-gaap_CommonStockCapitalSharesReservedForFutureIssuance-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="srt_RangeMember" xlink:type="locator"/>
    <link:label xlink:label="srt_RangeMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statistical Measurement [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_RangeMember" xlink:to="srt_RangeMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember" xlink:label="srt_MaximumMember" xlink:type="locator"/>
    <link:label xlink:label="srt_MaximumMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Maximum [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_MaximumMember" xlink:to="srt_MaximumMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember" xlink:label="srt_MinimumMember" xlink:type="locator"/>
    <link:label xlink:label="srt_MinimumMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Minimum [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_MinimumMember" xlink:to="srt_MinimumMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommitmentsAndContingenciesPolicyTextBlock" xlink:label="us-gaap_CommitmentsAndContingenciesPolicyTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_CommitmentsAndContingenciesPolicyTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Commitments and Contingencies, Policy [Policy Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommitmentsAndContingenciesPolicyTextBlock" xlink:to="us-gaap_CommitmentsAndContingenciesPolicyTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductOrServiceAxis" xlink:label="srt_ProductOrServiceAxis" xlink:type="locator"/>
    <link:label xlink:label="srt_ProductOrServiceAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Product and Service [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_ProductOrServiceAxis" xlink:to="srt_ProductOrServiceAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="srt_ProductsAndServicesDomain" xlink:type="locator"/>
    <link:label xlink:label="srt_ProductsAndServicesDomain-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Product and Service [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_ProductsAndServicesDomain" xlink:to="srt_ProductsAndServicesDomain-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:label="srt_RangeAxis" xlink:type="locator"/>
    <link:label xlink:label="srt_RangeAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statistical Measurement [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_RangeAxis" xlink:to="srt_RangeAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="srt_EquityMethodInvesteeNameDomain" xlink:type="locator"/>
    <link:label xlink:label="srt_EquityMethodInvesteeNameDomain-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Investment, Name [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_EquityMethodInvesteeNameDomain" xlink:to="srt_EquityMethodInvesteeNameDomain-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:type="locator"/>
    <link:label xlink:label="srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Investment, Name [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:to="srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxesPaid" xlink:label="us-gaap_IncomeTaxesPaid" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IncomeTaxesPaid-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash paid for income taxes</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxesPaid" xlink:to="us-gaap_IncomeTaxesPaid-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PrepaidExpenseCurrent" xlink:label="us-gaap_PrepaidExpenseCurrent" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PrepaidExpenseCurrent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Prepaid expenses</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PrepaidExpenseCurrent" xlink:to="us-gaap_PrepaidExpenseCurrent-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock" xlink:label="us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock" xlink:to="us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NoncurrentAssets" xlink:label="us-gaap_NoncurrentAssets" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_NoncurrentAssets-label" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Consolidated long-lived assets</link:label>
    <link:label xlink:label="us-gaap_NoncurrentAssets-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_NoncurrentAssets</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NoncurrentAssets" xlink:to="us-gaap_NoncurrentAssets-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock" xlink:label="us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment Disclosure [Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock" xlink:to="us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_StatementGeographicalAxis" xlink:label="srt_StatementGeographicalAxis" xlink:type="locator"/>
    <link:label xlink:label="srt_StatementGeographicalAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Geographical [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_StatementGeographicalAxis" xlink:to="srt_StatementGeographicalAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfRevenueByMajorCustomersByReportingSegmentsTableTextBlock" xlink:label="us-gaap_ScheduleOfRevenueByMajorCustomersByReportingSegmentsTableTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ScheduleOfRevenueByMajorCustomersByReportingSegmentsTableTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Revenue by Major Customers by Reporting Segments [Table Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfRevenueByMajorCustomersByReportingSegmentsTableTextBlock" xlink:to="us-gaap_ScheduleOfRevenueByMajorCustomersByReportingSegmentsTableTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_SegmentGeographicalDomain" xlink:label="srt_SegmentGeographicalDomain" xlink:type="locator"/>
    <link:label xlink:label="srt_SegmentGeographicalDomain-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Geographical [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_SegmentGeographicalDomain" xlink:to="srt_SegmentGeographicalDomain-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTextBlock" xlink:label="us-gaap_PropertyPlantAndEquipmentTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PropertyPlantAndEquipmentTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment [Table Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentTextBlock" xlink:to="us-gaap_PropertyPlantAndEquipmentTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GoodwillAndIntangibleAssetsGoodwillPolicy" xlink:label="us-gaap_GoodwillAndIntangibleAssetsGoodwillPolicy" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_GoodwillAndIntangibleAssetsGoodwillPolicy-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GoodwillAndIntangibleAssetsGoodwillPolicy" xlink:to="us-gaap_GoodwillAndIntangibleAssetsGoodwillPolicy-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsByGeographicalAreasTableTextBlock" xlink:label="us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsByGeographicalAreasTableTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsByGeographicalAreasTableTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Table Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsByGeographicalAreasTableTextBlock" xlink:to="us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsByGeographicalAreasTableTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InventoryNet" xlink:label="us-gaap_InventoryNet" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_InventoryNet-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Inventories</link:label>
    <link:label xlink:label="us-gaap_InventoryNet-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total inventory</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InventoryNet" xlink:to="us-gaap_InventoryNet-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GeographicAreasRevenuesFromExternalCustomersAbstract" xlink:label="us-gaap_GeographicAreasRevenuesFromExternalCustomersAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_GeographicAreasRevenuesFromExternalCustomersAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net sales by geographic region</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GeographicAreasRevenuesFromExternalCustomersAbstract" xlink:to="us-gaap_GeographicAreasRevenuesFromExternalCustomersAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax" xlink:label="us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net sales</link:label>
    <link:label xlink:label="us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Revenue from Contract with Customer, Including Assessed Tax</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax" xlink:to="us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxAssetsInvestments" xlink:label="us-gaap_DeferredTaxAssetsInvestments" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DeferredTaxAssetsInvestments-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Marketable securities</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredTaxAssetsInvestments" xlink:to="us-gaap_DeferredTaxAssetsInvestments-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GeographicAreasLongLivedAssetsAbstract" xlink:label="us-gaap_GeographicAreasLongLivedAssetsAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_GeographicAreasLongLivedAssetsAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-lived assets by geographic region</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GeographicAreasLongLivedAssetsAbstract" xlink:to="us-gaap_GeographicAreasLongLivedAssetsAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="us-gaap_FairValueInputsLevel3Member" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_FairValueInputsLevel3Member-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value, Inputs, Level 3 [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueInputsLevel3Member" xlink:to="us-gaap_FairValueInputsLevel3Member-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value Hierarchy and NAV [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:to="us-gaap_FairValueMeasurementsFairValueHierarchyDomain-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MajorCustomersAxis" xlink:label="srt_MajorCustomersAxis" xlink:type="locator"/>
    <link:label xlink:label="srt_MajorCustomersAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Customer [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_MajorCustomersAxis" xlink:to="srt_MajorCustomersAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel1Member" xlink:label="us-gaap_FairValueInputsLevel1Member" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_FairValueInputsLevel1Member-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value, Inputs, Level 1 [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueInputsLevel1Member" xlink:to="us-gaap_FairValueInputsLevel1Member-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_NameOfMajorCustomerDomain" xlink:label="srt_NameOfMajorCustomerDomain" xlink:type="locator"/>
    <link:label xlink:label="srt_NameOfMajorCustomerDomain-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Customer [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_NameOfMajorCustomerDomain" xlink:to="srt_NameOfMajorCustomerDomain-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="us-gaap_FairValueInputsLevel2Member" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_FairValueInputsLevel2Member-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value, Inputs, Level 2 [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueInputsLevel2Member" xlink:to="us-gaap_FairValueInputsLevel2Member-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReconciliationOfAssetsFromSegmentToConsolidatedTextBlock" xlink:label="us-gaap_ReconciliationOfAssetsFromSegmentToConsolidatedTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ReconciliationOfAssetsFromSegmentToConsolidatedTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Reconciliation of Assets from Segment to Consolidated [Table Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ReconciliationOfAssetsFromSegmentToConsolidatedTextBlock" xlink:to="us-gaap_ReconciliationOfAssetsFromSegmentToConsolidatedTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_FairValueByFairValueHierarchyLevelAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value Hierarchy and NAV [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:to="us-gaap_FairValueByFairValueHierarchyLevelAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReconciliationOfRevenueFromSegmentsToConsolidatedTextBlock" xlink:label="us-gaap_ReconciliationOfRevenueFromSegmentsToConsolidatedTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ReconciliationOfRevenueFromSegmentsToConsolidatedTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Reconciliation of Revenue from Segments to Consolidated [Table Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ReconciliationOfRevenueFromSegmentsToConsolidatedTextBlock" xlink:to="us-gaap_ReconciliationOfRevenueFromSegmentsToConsolidatedTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLife-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property and equipment (Year)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:to="us-gaap_PropertyPlantAndEquipmentUsefulLife-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash Flows From Operating Activities:</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Segment Reporting Information, by Segment [Table Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock" xlink:to="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueRecognitionPolicyTextBlock" xlink:label="us-gaap_RevenueRecognitionPolicyTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_RevenueRecognitionPolicyTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revenue [Policy Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RevenueRecognitionPolicyTextBlock" xlink:to="us-gaap_RevenueRecognitionPolicyTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_CustomerDMember" xlink:label="apt_CustomerDMember" xlink:type="locator"/>
    <link:label xlink:label="apt_CustomerDMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Customer D [Member]</link:label>
    <link:label xlink:label="apt_CustomerDMember-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents information about customer D.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_CustomerDMember" xlink:to="apt_CustomerDMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_StatementLineItems-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statement [Line Items]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementLineItems-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent" xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Allowance for doubtful accounts</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent" xlink:to="us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NumberOfOperatingSegments" xlink:label="us-gaap_NumberOfOperatingSegments" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_NumberOfOperatingSegments-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_NumberOfOperatingSegments</link:label>
    <link:label xlink:label="us-gaap_NumberOfOperatingSegments-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of Operating Segments</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NumberOfOperatingSegments" xlink:to="us-gaap_NumberOfOperatingSegments-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FurnitureAndFixturesMember" xlink:label="us-gaap_FurnitureAndFixturesMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_FurnitureAndFixturesMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Furniture and Fixtures [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FurnitureAndFixturesMember" xlink:to="us-gaap_FurnitureAndFixturesMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="us-gaap_AccountsReceivableNetCurrent" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AccountsReceivableNetCurrent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounts receivable, net of allowance for doubtful accounts of $71,000 as of December 31, 2020 and $53,000 as of December 31, 2019</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccountsReceivableNetCurrent" xlink:to="us-gaap_AccountsReceivableNetCurrent-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BuildingMember" xlink:label="us-gaap_BuildingMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_BuildingMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Building [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BuildingMember" xlink:to="us-gaap_BuildingMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdditionalPaidInCapitalCommonStock" xlink:label="us-gaap_AdditionalPaidInCapitalCommonStock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AdditionalPaidInCapitalCommonStock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Additional paid-in capital</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AdditionalPaidInCapitalCommonStock" xlink:to="us-gaap_AdditionalPaidInCapitalCommonStock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">AOCI Attributable to Parent [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquityAbstract" xlink:label="us-gaap_StockholdersEquityAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_StockholdersEquityAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Shareholders' equity:</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LeaseholdImprovementsMember" xlink:label="us-gaap_LeaseholdImprovementsMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_LeaseholdImprovementsMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Leasehold Improvements [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LeaseholdImprovementsMember" xlink:to="us-gaap_LeaseholdImprovementsMember-label" xlink:type="arc"/>
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    <link:label xlink:label="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment, Policy [Policy Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock" xlink:to="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Lived Tangible Asset [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:to="us-gaap_PropertyPlantAndEquipmentByTypeAxis-label" xlink:type="arc"/>
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    <link:label xlink:label="us-gaap_NonoperatingIncomeExpense-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_NonoperatingIncomeExpense</link:label>
    <link:label xlink:label="us-gaap_NonoperatingIncomeExpense-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total other income</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NonoperatingIncomeExpense" xlink:to="us-gaap_NonoperatingIncomeExpense-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentReportingDisclosureTextBlock" xlink:label="us-gaap_SegmentReportingDisclosureTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_SegmentReportingDisclosureTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Segment Reporting Disclosure [Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SegmentReportingDisclosureTextBlock" xlink:to="us-gaap_SegmentReportingDisclosureTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Lived Tangible Asset [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="us-gaap_PropertyPlantAndEquipmentTypeDomain-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsCurrentAbstract" xlink:label="us-gaap_AssetsCurrentAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AssetsCurrentAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Current assets:</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AssetsCurrentAbstract" xlink:to="us-gaap_AssetsCurrentAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations</link:label>
    <link:label xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations-label" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xml:lang="en-US">Cash and cash equivalents, beginning of the year</link:label>
    <link:label xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations-label" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">Cash and cash equivalents, end of the year</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations" xlink:to="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InventoryPolicyTextBlock" xlink:label="us-gaap_InventoryPolicyTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_InventoryPolicyTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Inventory, Policy [Policy Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InventoryPolicyTextBlock" xlink:to="us-gaap_InventoryPolicyTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsAbstract" xlink:label="us-gaap_AssetsAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AssetsAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Assets:</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AssetsAbstract" xlink:to="us-gaap_AssetsAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect</link:label>
    <link:label xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Increase (decrease) in cash and cash equivalents</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:to="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Liabilities" xlink:label="us-gaap_Liabilities" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_Liabilities-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_Liabilities</link:label>
    <link:label xlink:label="us-gaap_Liabilities-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Liabilities, Total</link:label>
    <link:label xlink:label="us-gaap_Liabilities-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total liabilities</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_Liabilities" xlink:to="us-gaap_Liabilities-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_NetCashProvidedByUsedInFinancingActivities</link:label>
    <link:label xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net cash used in financing activities</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivities-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommitmentsAndContingencies" xlink:label="us-gaap_CommitmentsAndContingencies" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_CommitmentsAndContingencies-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Commitments</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommitmentsAndContingencies" xlink:to="us-gaap_CommitmentsAndContingencies-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="us-gaap_OperatingIncomeLoss" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_OperatingIncomeLoss-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_OperatingIncomeLoss</link:label>
    <link:label xlink:label="us-gaap_OperatingIncomeLoss-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Income from operations</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingIncomeLoss" xlink:to="us-gaap_OperatingIncomeLoss-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_NetCashProvidedByUsedInOperatingActivities</link:label>
    <link:label xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net cash provided by operating activities</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivities-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxLiabilitiesOther" xlink:label="us-gaap_DeferredTaxLiabilitiesOther" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DeferredTaxLiabilitiesOther-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_DeferredTaxLiabilitiesOther</link:label>
    <link:label xlink:label="us-gaap_DeferredTaxLiabilitiesOther-label" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Other</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredTaxLiabilitiesOther" xlink:to="us-gaap_DeferredTaxLiabilitiesOther-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NonoperatingIncomeExpenseAbstract" xlink:label="us-gaap_NonoperatingIncomeExpenseAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_NonoperatingIncomeExpenseAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other income (expense):</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NonoperatingIncomeExpenseAbstract" xlink:to="us-gaap_NonoperatingIncomeExpenseAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_NetCashProvidedByUsedInInvestingActivities</link:label>
    <link:label xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net cash used in investing activities</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivities-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxLiabilities" xlink:label="us-gaap_DeferredTaxLiabilities" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DeferredTaxLiabilities-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_DeferredTaxLiabilities</link:label>
    <link:label xlink:label="us-gaap_DeferredTaxLiabilities-label" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Net deferred income tax liabilities</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredTaxLiabilities" xlink:to="us-gaap_DeferredTaxLiabilities-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets" xlink:label="us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets</link:label>
    <link:label xlink:label="us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets-label" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Intangible assets</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GrossProfit" xlink:label="us-gaap_GrossProfit" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_GrossProfit-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_GrossProfit</link:label>
    <link:label xlink:label="us-gaap_GrossProfit-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Gross profit</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CostOfGoodsAndServicesSold" xlink:label="us-gaap_CostOfGoodsAndServicesSold" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_CostOfGoodsAndServicesSold-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cost of goods sold, excluding depreciation and amortization</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CostOfGoodsAndServicesSold" xlink:to="us-gaap_CostOfGoodsAndServicesSold-label" xlink:type="arc"/>
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    <link:label xlink:label="us-gaap_DeferredIncomeTaxLiabilitiesNet-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred income tax liabilities, net</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredIncomeTaxLiabilitiesNet" xlink:to="us-gaap_DeferredIncomeTaxLiabilitiesNet-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidationItemsDomain" xlink:label="srt_ConsolidationItemsDomain" xlink:type="locator"/>
    <link:label xlink:label="srt_ConsolidationItemsDomain-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Consolidation Items [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_ConsolidationItemsDomain" xlink:to="srt_ConsolidationItemsDomain-label" xlink:type="arc"/>
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    <link:label xlink:label="srt_ReportableGeographicalComponentsMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Reportable Geographical Components [Member]</link:label>
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    <link:label xlink:label="us-gaap_EquityMethodInvestmentAggregateCost-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_EquityMethodInvestmentAggregateCost</link:label>
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    <link:label xlink:label="us-gaap_ContractWithCustomerLiability-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_ContractWithCustomerLiability</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ContractWithCustomerLiability" xlink:to="us-gaap_ContractWithCustomerLiability-label" xlink:type="arc"/>
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    <link:label xlink:label="srt_ConsolidationItemsAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Consolidation Items [Axis]</link:label>
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    <link:label xlink:label="us-gaap_MarketableSecuritiesPolicy-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Marketable Securities, Policy [Policy Text Block]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TypeOfAdoptionMember" xlink:to="us-gaap_TypeOfAdoptionMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxLiabilitiesUnrealizedCurrencyTransactionGains" xlink:label="us-gaap_DeferredTaxLiabilitiesUnrealizedCurrencyTransactionGains" xlink:type="locator"/>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredTaxLiabilitiesUnrealizedCurrencyTransactionGains" xlink:to="us-gaap_DeferredTaxLiabilitiesUnrealizedCurrencyTransactionGains-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment" xlink:label="us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment" xlink:to="us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:label="us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:type="locator"/>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:to="us-gaap_AdjustmentsForNewAccountingPronouncementsAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_OfficerMember" xlink:label="srt_OfficerMember" xlink:type="locator"/>
    <link:label xlink:label="srt_OfficerMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Officer [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_OfficerMember" xlink:to="srt_OfficerMember-label" xlink:type="arc"/>
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    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_PresidentMember" xlink:label="srt_PresidentMember" xlink:type="locator"/>
    <link:label xlink:label="srt_PresidentMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">President [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_PresidentMember" xlink:to="srt_PresidentMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsForRepurchaseOfCommonStock" xlink:label="us-gaap_PaymentsForRepurchaseOfCommonStock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_PaymentsForRepurchaseOfCommonStock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_PaymentsForRepurchaseOfCommonStock</link:label>
    <link:label xlink:label="us-gaap_PaymentsForRepurchaseOfCommonStock-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Payments for Repurchase of Common Stock</link:label>
    <link:label xlink:label="us-gaap_PaymentsForRepurchaseOfCommonStock-label" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Repurchase of common stock</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsForRepurchaseOfCommonStock" xlink:to="us-gaap_PaymentsForRepurchaseOfCommonStock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:label="us-gaap_RetainedEarningsMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_RetainedEarningsMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Retained Earnings [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RetainedEarningsMember" xlink:to="us-gaap_RetainedEarningsMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromStockOptionsExercised" xlink:label="us-gaap_ProceedsFromStockOptionsExercised" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ProceedsFromStockOptionsExercised-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_ProceedsFromStockOptionsExercised</link:label>
    <link:label xlink:label="us-gaap_ProceedsFromStockOptionsExercised-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from Stock Options Exercised</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:type="locator"/>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:to="srt_TitleOfIndividualWithRelationshipToEntityDomain-label" xlink:type="arc"/>
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    <link:label xlink:label="srt_TitleOfIndividualAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Title of Individual [Axis]</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:label="us-gaap_AdditionalPaidInCapitalMember" xlink:type="locator"/>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AdditionalPaidInCapitalMember" xlink:to="us-gaap_AdditionalPaidInCapitalMember-label" xlink:type="arc"/>
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    <link:label xlink:label="us-gaap_CommonStockMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common Stock [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockMember" xlink:to="us-gaap_CommonStockMember-label" xlink:type="arc"/>
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    <link:label xlink:label="us-gaap_CurrentIncomeTaxExpenseBenefit-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Current</link:label>
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    <link:loc xlink:href="apt-20201231.xsd#apt_NumberOfStoresOwned" xlink:label="apt_NumberOfStoresOwned" xlink:type="locator"/>
    <link:label xlink:label="apt_NumberOfStoresOwned-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">apt_NumberOfStoresOwned</link:label>
    <link:label xlink:label="apt_NumberOfStoresOwned-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number Of Stores Owned</link:label>
    <link:label xlink:label="apt_NumberOfStoresOwned-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the number of stores owned.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_NumberOfStoresOwned" xlink:to="apt_NumberOfStoresOwned-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MachineryAndEquipmentMember" xlink:label="us-gaap_MachineryAndEquipmentMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_MachineryAndEquipmentMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Machinery and Equipment [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MachineryAndEquipmentMember" xlink:to="us-gaap_MachineryAndEquipmentMember-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_NumberOfStoresRented" xlink:label="apt_NumberOfStoresRented" xlink:type="locator"/>
    <link:label xlink:label="apt_NumberOfStoresRented-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">apt_NumberOfStoresRented</link:label>
    <link:label xlink:label="apt_NumberOfStoresRented-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number Of Stores Rented</link:label>
    <link:label xlink:label="apt_NumberOfStoresRented-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the number of stores rented.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_NumberOfStoresRented" xlink:to="apt_NumberOfStoresRented-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashAndCashEquivalentsPolicyTextBlock" xlink:label="us-gaap_CashAndCashEquivalentsPolicyTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_CashAndCashEquivalentsPolicyTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash and Cash Equivalents, Policy [Policy Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CashAndCashEquivalentsPolicyTextBlock" xlink:to="us-gaap_CashAndCashEquivalentsPolicyTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReceivablesPolicyTextBlock" xlink:label="us-gaap_ReceivablesPolicyTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ReceivablesPolicyTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Receivable [Policy Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ReceivablesPolicyTextBlock" xlink:to="us-gaap_ReceivablesPolicyTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SoftwareDevelopmentMember" xlink:label="us-gaap_SoftwareDevelopmentMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_SoftwareDevelopmentMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Software Development [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SoftwareDevelopmentMember" xlink:to="us-gaap_SoftwareDevelopmentMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountingPoliciesAbstract" xlink:label="us-gaap_AccountingPoliciesAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AccountingPoliciesAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounting Policies [Abstract]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_AccountingPoliciesAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SignificantAccountingPoliciesTextBlock" xlink:label="us-gaap_SignificantAccountingPoliciesTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_SignificantAccountingPoliciesTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Significant Accounting Policies [Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SignificantAccountingPoliciesTextBlock" xlink:to="us-gaap_SignificantAccountingPoliciesTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BasisOfAccountingPolicyPolicyTextBlock" xlink:label="us-gaap_BasisOfAccountingPolicyPolicyTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_BasisOfAccountingPolicyPolicyTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Basis of Accounting, Policy [Policy Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BasisOfAccountingPolicyPolicyTextBlock" xlink:to="us-gaap_BasisOfAccountingPolicyPolicyTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskDisclosureTextBlock" xlink:label="us-gaap_ConcentrationRiskDisclosureTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ConcentrationRiskDisclosureTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk Disclosure [Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConcentrationRiskDisclosureTextBlock" xlink:to="us-gaap_ConcentrationRiskDisclosureTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityInteractiveDataCurrent" xlink:label="dei_EntityInteractiveDataCurrent" xlink:type="locator"/>
    <link:label xlink:label="dei_EntityInteractiveDataCurrent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Interactive Data Current</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityInteractiveDataCurrent" xlink:to="dei_EntityInteractiveDataCurrent-label" xlink:type="arc"/>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_Security12bTitle" xlink:label="dei_Security12bTitle" xlink:type="locator"/>
    <link:label xlink:label="dei_Security12bTitle-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Title of 12(b) Security</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_Security12bTitle" xlink:to="dei_Security12bTitle-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_PropertyPlantAndEquipmentUsefulLivesTableTextBlock" xlink:label="apt_PropertyPlantAndEquipmentUsefulLivesTableTextBlock" xlink:type="locator"/>
    <link:label xlink:label="apt_PropertyPlantAndEquipmentUsefulLivesTableTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant, and Equipment, Useful Lives [Table Text Block]</link:label>
    <link:label xlink:label="apt_PropertyPlantAndEquipmentUsefulLivesTableTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Tabular disclosure of useful life of long lived, physical assets used in the normal conduct of business and not intended for resale.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_PropertyPlantAndEquipmentUsefulLivesTableTextBlock" xlink:to="apt_PropertyPlantAndEquipmentUsefulLivesTableTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis" xlink:label="us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Legal Entity of Counterparty, Type [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis" xlink:to="us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LegalEntityTypeOfCounterpartyDomain" xlink:label="us-gaap_LegalEntityTypeOfCounterpartyDomain" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_LegalEntityTypeOfCounterpartyDomain-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Legal Entity Type of Counterparty [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LegalEntityTypeOfCounterpartyDomain" xlink:to="us-gaap_LegalEntityTypeOfCounterpartyDomain-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="us-gaap_StatementBusinessSegmentsAxis" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_StatementBusinessSegmentsAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Segments [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementBusinessSegmentsAxis" xlink:to="us-gaap_StatementBusinessSegmentsAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain" xlink:label="us-gaap_SegmentDomain" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_SegmentDomain-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Segments [Domain]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SegmentDomain" xlink:to="us-gaap_SegmentDomain-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeLossAttributableToParent" xlink:label="us-gaap_IncomeLossAttributableToParent" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IncomeLossAttributableToParent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_IncomeLossAttributableToParent</link:label>
    <link:label xlink:label="us-gaap_IncomeLossAttributableToParent-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Income before provision for income taxes</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeLossAttributableToParent" xlink:to="us-gaap_IncomeLossAttributableToParent-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount</link:label>
    <link:label xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:to="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:label="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Diluted weighted average common shares outstanding (in shares)</link:label>
    <link:label xlink:label="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Diluted weighted average common shares outstanding (in shares)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:to="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_StatementTable-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statement [Table]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_StatementTable-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementOfFinancialPositionAbstract" xlink:label="us-gaap_StatementOfFinancialPositionAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_StatementOfFinancialPositionAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statement of Financial Position [Abstract]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementOfFinancialPositionAbstract" xlink:to="us-gaap_StatementOfFinancialPositionAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EarningsPerShareDiluted" xlink:label="us-gaap_EarningsPerShareDiluted" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_EarningsPerShareDiluted-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Diluted earnings per common share (in dollars per share)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EarningsPerShareDiluted" xlink:to="us-gaap_EarningsPerShareDiluted-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Basic weighted average common shares outstanding (in shares)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:to="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock" xlink:label="us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounts Payable and Accrued Liabilities Disclosure [Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock" xlink:to="us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EarningsPerShareBasic" xlink:label="us-gaap_EarningsPerShareBasic" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_EarningsPerShareBasic-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Basic earnings per common share (in dollars per share)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EarningsPerShareBasic" xlink:to="us-gaap_EarningsPerShareBasic-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementOfCashFlowsAbstract" xlink:label="us-gaap_StatementOfCashFlowsAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_StatementOfCashFlowsAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statement of Cash Flows [Abstract]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementOfCashFlowsAbstract" xlink:to="us-gaap_StatementOfCashFlowsAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesCurrent" xlink:label="us-gaap_AvailableForSaleSecuritiesCurrent" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AvailableForSaleSecuritiesCurrent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Investment</link:label>
    <link:label xlink:label="us-gaap_AvailableForSaleSecuritiesCurrent-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Available-for-sale Securities, Current, Total</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AvailableForSaleSecuritiesCurrent" xlink:to="us-gaap_AvailableForSaleSecuritiesCurrent-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementOfStockholdersEquityAbstract" xlink:label="us-gaap_StatementOfStockholdersEquityAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_StatementOfStockholdersEquityAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statement of Stockholders' Equity [Abstract]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementOfStockholdersEquityAbstract" xlink:to="us-gaap_StatementOfStockholdersEquityAbstract-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementAbstract" xlink:label="us-gaap_IncomeStatementAbstract" xlink:type="locator"/>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfAccruedLiabilitiesTableTextBlock" xlink:label="us-gaap_ScheduleOfAccruedLiabilitiesTableTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ScheduleOfAccruedLiabilitiesTableTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Accrued Liabilities [Table Text Block]</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock" xlink:label="us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock" xlink:label="us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Deferred Tax Assets and Liabilities [Table Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock" xlink:to="us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock" xlink:label="us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisTextBlock" xlink:label="us-gaap_FairValueAssetsMeasuredOnRecurringBasisTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_FairValueAssetsMeasuredOnRecurringBasisTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value, Assets Measured on Recurring Basis [Table Text Block]</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash Flows From Financing Activities:</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxReconciliationOtherReconcilingItems" xlink:label="us-gaap_IncomeTaxReconciliationOtherReconcilingItems" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IncomeTaxReconciliationOtherReconcilingItems-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital" xlink:label="us-gaap_ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital</link:label>
    <link:label xlink:label="us-gaap_ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from Equity Method Investment, Distribution, Return of Capital</link:label>
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    <link:loc xlink:href="apt-20201231.xsd#apt_FormerCeoMember" xlink:label="apt_FormerCeoMember" xlink:type="locator"/>
    <link:label xlink:label="apt_FormerCeoMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Former CEO [Member]</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CorporateNonSegmentMember" xlink:label="us-gaap_CorporateNonSegmentMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_CorporateNonSegmentMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Corporate, Non-Segment [Member]</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsReceivableRelatedPartiesCurrent" xlink:label="us-gaap_AccountsReceivableRelatedPartiesCurrent" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AccountsReceivableRelatedPartiesCurrent-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounts receivable, related party</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccountsReceivableRelatedPartiesCurrent" xlink:to="us-gaap_AccountsReceivableRelatedPartiesCurrent-label" xlink:type="arc"/>
    <link:loc xlink:href="apt-20201231.xsd#apt_IncentivePlan2020Member" xlink:label="apt_IncentivePlan2020Member" xlink:type="locator"/>
    <link:label xlink:label="apt_IncentivePlan2020Member-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Incentive Plan 2020 [Member]</link:label>
    <link:label xlink:label="apt_IncentivePlan2020Member-label" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the 2020 incentive plan.</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="apt_IncentivePlan2020Member" xlink:to="apt_IncentivePlan2020Member-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="us-gaap_StockholdersEquity" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_StockholdersEquity-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_StockholdersEquity</link:label>
    <link:label xlink:label="us-gaap_StockholdersEquity-label" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total shareholders' equity</link:label>
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    <link:label xlink:label="us-gaap_StockholdersEquity-label" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">Balance</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockholdersEquity" xlink:to="us-gaap_StockholdersEquity-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="us-gaap_StatementClassOfStockAxis" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_StatementClassOfStockAxis-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Class of Stock [Axis]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementClassOfStockAxis" xlink:to="us-gaap_StatementClassOfStockAxis-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock" xlink:label="us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock" xlink:to="us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageRemainingContractualTerm2" xlink:label="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageRemainingContractualTerm2" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageRemainingContractualTerm2-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Options Exercisable, Weighted Average Remaining Contract Life (Year)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageRemainingContractualTerm2" xlink:to="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageRemainingContractualTerm2-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxReconciliationNondeductibleExpenseMealsAndEntertainment" xlink:label="us-gaap_IncomeTaxReconciliationNondeductibleExpenseMealsAndEntertainment" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IncomeTaxReconciliationNondeductibleExpenseMealsAndEntertainment-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Non-deductible meals and entertainment</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxReconciliationNondeductibleExpenseMealsAndEntertainment" xlink:to="us-gaap_IncomeTaxReconciliationNondeductibleExpenseMealsAndEntertainment-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax</link:label>
    <link:label xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" xlink:to="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1" xlink:label="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Options Outstanding, Weighted Average Exercise Price (in dollars per share)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1" xlink:to="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax</link:label>
    <link:label xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax-label" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax" xlink:to="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2" xlink:label="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Options Outstanding, Weighted Average Remaining Contract Life (Year)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2" xlink:to="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions" xlink:label="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Options Exercisable, Options (in shares)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions" xlink:to="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1" xlink:label="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Options Exercisable, Weighted Average Exercise Price (in dollars per share)</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1" xlink:to="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingSegmentsMember" xlink:label="us-gaap_OperatingSegmentsMember" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_OperatingSegmentsMember-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Segments [Member]</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingSegmentsMember" xlink:to="us-gaap_OperatingSegmentsMember-label" xlink:type="arc"/>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxReconciliationTaxCreditsForeign" xlink:label="us-gaap_IncomeTaxReconciliationTaxCreditsForeign" xlink:type="locator"/>
    <link:label xlink:label="us-gaap_IncomeTaxReconciliationTaxCreditsForeign-label" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">us-gaap_IncomeTaxReconciliationTaxCreditsForeign</link:label>
    <link:label xlink:label="us-gaap_IncomeTaxReconciliationTaxCreditsForeign-label" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">FDII deduction</link:label>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxReconciliationTaxCreditsForeign" xlink:to="us-gaap_IncomeTaxReconciliationTaxCreditsForeign-label" xlink:type="arc"/>
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