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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OciBeforeReclassificationsBeforeTaxAttributableToParent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other comprehensive income (loss) before reclassifications, before income tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OciBeforeReclassificationsBeforeTaxAttributableToParent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">OCI, before Reclassifications, before Tax, Attributable to Parent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Contingencies</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Commitments and Contingencies Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesAuthorized_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common shares, authorized (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesAuthorized_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock, Shares Authorized</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ProductOrServiceAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Product and Service</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ProductOrServiceAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Product and Service [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentFiscalPeriodFocus_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document Fiscal Period Focus</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentFiscalPeriodFocus_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Fiscal Period Focus</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accrued pension and postretirement costs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Liability, Defined Benefit Plan, Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountingStandardsUpdate202309Member_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounting Standards Update 2023-09 [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountingStandardsUpdate202309Member_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">ASU 2023-09</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RevenueFromContractWithCustomerAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Revenue from Contract with Customer [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityShellCompany_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Shell Company</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityShellCompany_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Shell Company</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherAccruedLiabilitiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other current liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherAccruedLiabilitiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Accrued Liabilities, Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InventoryGross_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Gross inventory</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InventoryGross_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Inventory, Gross</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ConvertibleDebtMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Convertible Notes</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ConvertibleDebtMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Convertible Debt [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Cash and Cash Equivalents, at Carrying Value, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Cash and Cash Equivalents, at Carrying Value, Beginning Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Cash and Cash Equivalents, at Carrying Value, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash and cash equivalents</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash and Cash Equivalent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesIssued_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Common Stock, Shares, Issued, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesIssued_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common shares, issued (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesIssued_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock, Shares, Issued</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ForeignPlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Foreign Plan [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Statement [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInPrepaidExpense_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Deferred charges and prepaid expenses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInPrepaidExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase (Decrease) in Prepaid Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Statement [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TreasuryStockValueAcquiredCostMethod_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Shares surrendered for taxes</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TreasuryStockValueAcquiredCostMethod_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Treasury Stock, Value, Acquired, Cost Method</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TreasuryStockValueAcquiredCostMethod_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Purchase of treasury shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityFilerCategory_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Filer Category</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityFilerCategory_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Filer Category</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Settlement gain</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Net remeasurement losses (gains)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total Liabilities and Shareholders&#8217; Equity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Liabilities and Equity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt Instrument [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Long-term Debt, Current Maturities, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Less current portion of debt</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Term Debt, Current Maturities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsequentEventLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Subsequent Event [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperations_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Effective Income Tax Rate Reconciliation, Percent, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperations_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Effective tax rate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperations_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Effective Income Tax Rate Reconciliation, Percent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxesPaid_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Taxes Paid</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxesPaid_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Income Taxes Paid</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InvestmentIncomeInterest_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Interest income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InvestmentIncomeInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InvestmentIncomeInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Investment Income, Interest</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InventoryFinishedGoods_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Inventory, Finished Goods, Gross, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InventoryFinishedGoods_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Finished products</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InventoryFinishedGoods_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Inventory, Finished Goods, Gross</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_ContractLiabalitiesTotalated_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Contract liabilities totaled</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_ContractLiabalitiesTotalated_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Contract liabalities totalated</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_ContractLiabalitiesTotalated_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Contract liabalities totalated.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfInventoryCurrentTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Components of Inventory</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfInventoryCurrentTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Inventory, Current [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivable_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Accounts Receivable, Allowance for Credit Loss, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivable_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Accounts Receivable, Allowance for Credit Loss, Beginning Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Allowances for accounts receivable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounts Receivable, Allowance for Credit Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdditionalPaidInCapitalCommonStock_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Additional Paid in Capital, Common Stock, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdditionalPaidInCapitalCommonStock_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Additional Paid in Capital, Common Stock, Beginning Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdditionalPaidInCapitalCommonStock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Additional paid-in capital</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdditionalPaidInCapitalCommonStock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Additional Paid in Capital, Common Stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_FutureAllocatedShareBasedCompensationExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Future stock-based compensation expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_FutureAllocatedShareBasedCompensationExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Future Allocated Share Based Compensation Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_FutureAllocatedShareBasedCompensationExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Future allocated share based compensation expense.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_PensionAndOtherPostretirementBenefitsExpenseReversalOfExpenseNoncashExcludingMarkToMarketAdjustments_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Pension and postretirement (benefit) expense, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_PensionAndOtherPostretirementBenefitsExpenseReversalOfExpenseNoncashExcludingMarkToMarketAdjustments_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Pension And Other Postretirement Benefits Expense Reversal Of Expense Noncash Excluding Mark To Market Adjustments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_PensionAndOtherPostretirementBenefitsExpenseReversalOfExpenseNoncashExcludingMarkToMarketAdjustments_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Pension and Other Postretirement Benefits Expense (Reversal of Expense), Noncash, Excluding Mark-to-Market Adjustments.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_KristineCSyrvalinMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Kristine C. Syrvalin [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_KristineCSyrvalinMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Kristine C. Syrvalin.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock options, shares granted</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisaggregationOfRevenueTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Disaggregation Of Revenue [Table]</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Earnings (Loss) Per Share, Basic and Diluted</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Increase (Decrease) in Other Operating Assets and Liabilities, Net, Total</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AOCIAttributableToParentNetOfTaxRollForward_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">AOCI Attributable to Parent, Net of Tax [Roll Forward]</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockCompensationPlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Payment Arrangement [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockCompensationPlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Equity-based Awards</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareBasic_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Earnings Per Share, Basic, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareBasic_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Basic earnings (loss) per share</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareBasic_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Earnings Per Share, Basic</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareBasic_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Basic earnings (loss) per share</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisaggregationOfRevenueTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Disaggregation of Revenue</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisaggregationOfRevenueTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Disaggregation of Revenue [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Retirement and Postretirement Plans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Retirement Benefits [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Foreign currency translation adjustments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RevolvingCreditFacilityMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Credit Agreement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RevolvingCreditFacilityMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Revolving Credit Facility [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetirementPlanTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Retirement Plan Type</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetirementPlanTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Retirement Plan Type [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total Current Liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Liabilities, Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GovernmentAssistanceAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Government Assistance [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInAccountsReceivable_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Accounts receivable, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInAccountsReceivable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase (Decrease) in Accounts Receivable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Adjustments to reconcile net income (loss) to net cash provided (used) by operating activities:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DomesticCountryMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Domestic Tax Jurisdiction [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DomesticCountryMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">U.S.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GovernmentAssistanceAwardAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Government Assistance, Award Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GovernmentAssistanceAwardAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Government funding</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounting Standards Update [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_FourthAmendedCreditFacilityMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Fourth amended credit facility member.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_FourthAmendedCreditFacilityMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fourth Amended Credit Facility [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_FourthAmendedCreditFacilityMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fourth Amended Credit Facility</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_FourthAmendedCreditFacilityMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Credit Agreement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_CashHeldInOtherInvestments_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash Held In Other Investments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_CashHeldInOtherInvestments_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Cash held in other investments.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_CashHeldInOtherInvestments_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash held in other investments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Shareholders&#8217; Equity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Equity, Attributable to Parent [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_PensionCostAndOtherPostretirementBenefitsCostPlanGainOnAnnuitization_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Pension cost and other postretirement benefits cost plan gain on annuitization.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_PensionCostAndOtherPostretirementBenefitsCostPlanGainOnAnnuitization_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Pension Cost and Other Postretirement Benefits Cost Plan Gain on Annuitization</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_PensionCostAndOtherPostretirementBenefitsCostPlanGainOnAnnuitization_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Gain on plan asset annuitization</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntitySmallBusiness_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Small Business</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntitySmallBusiness_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Small Business</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInAccruedLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other accrued expenses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInAccruedLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase (Decrease) in Accrued Liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInAccruedLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Increase (Decrease) in Accrued Liabilities, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Retained Earnings (Accumulated Deficit), Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Retained Earnings (Accumulated Deficit), Beginning Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Retained Earnings (Accumulated Deficit), Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Retained deficit</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Retained deficit</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Retained Earnings (Accumulated Deficit)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock-Based Compensation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Payment Arrangement [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Organization, Consolidation and Presentation of Financial Statements [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncrementalCommonSharesAttributableToConversionOfDebtSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Incremental Common Shares Attributable to Conversion of Debt Securities, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncrementalCommonSharesAttributableToConversionOfDebtSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Dilutive effect of convertible notes (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncrementalCommonSharesAttributableToConversionOfDebtSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InventoryValuationReserves_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Inventory Valuation Reserves, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InventoryValuationReserves_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Inventory Valuation Reserves, Beginning Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InventoryValuationReserves_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Allowance for inventory reserves</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InventoryValuationReserves_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Inventory Valuation Reserves</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_AmendmentFlag_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Amendment Flag</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_AmendmentFlag_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Amendment Flag</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ProductsAndServicesDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Product and Service</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ProductsAndServicesDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Product and Service [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InventoryDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Inventories</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InventoryDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Inventory Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesAndStockholdersEquityAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">LIABILITIES AND SHAREHOLDERS&#8217; EQUITY</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesAndStockholdersEquityAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Liabilities and Equity [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressPostalZipCode_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Address, Postal Zip Code</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressPostalZipCode_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address, Postal Zip Code</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net Cash Provided (Used) by Operating Activities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash Provided by (Used in) Operating Activity, Including Discontinued Operation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_LineofCreditFacilityTentativeFutureCommitmentIncrease_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Line of Credit Facility, Tentative Future Commitment Increase</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_LineofCreditFacilityTentativeFutureCommitmentIncrease_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lineof Credit Facility Tentative Future Commitment Increase</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_LineofCreditFacilityTentativeFutureCommitmentIncrease_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Line of credit facility, tentative future commitment increase</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingCodmProfitLossMeasureHowUsedDescription_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Segment Reporting, CODM, Profit (Loss) Measure, How Used, Description</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common Shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">New Accounting Pronouncements Or Change In Accounting Principle [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounting Standards Update and Change in Accounting Principle [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_OtherProductsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_OtherProductsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Products [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_OtherProductsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other Products [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Pension assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Assets for Plan Benefits, Defined Benefit Plan</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountingStandardsUpdate202403Member_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounting Standards Update 2024-03 [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountingStandardsUpdate202403Member_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">ASU 2024-03</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_FirstInLastOutFILOMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">First In, Last Out (FILO) [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_FirstInLastOutFILOMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">First In Last Out F I L O [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_FirstInLastOutFILOMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">First In, Last Out (FILO)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressAddressLine1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Address, Address Line One</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressAddressLine1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address, Address Line One</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentConvertibleThresholdPercentageOfStockPriceTrigger_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt Instrument, threshold Percentage of stock price conversion</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentConvertibleThresholdPercentageOfStockPriceTrigger_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument, Convertible, Threshold Percentage of Stock Price Trigger</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Per Share Data:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Earnings Per Share [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LossContingencyAccrualDisclosuresAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loss Contingency Accrual, Disclosures [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseRightOfUseAsset_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating lease right-of-use assets</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentType_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Document Type</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentType_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Type</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GrossProfit_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Gross Profit</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GrossProfit_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Gross Profit</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestOnConvertibleDebtNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest on Convertible Debt, Net of Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityCentralIndexKey_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Central Index Key</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityCentralIndexKey_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Central Index Key</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestrictedCashAndCashEquivalentsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restricted Cash and Cash Equivalent [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Increase (Decrease) in Cash, Cash Equivalents, and Restricted Cash</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsequentEventTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Subsequent Event Type [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Antidilutive securities excluded from calculation of computation of diluted earnings (loss) per share</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stock Repurchased and Retired During Period, Shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock Repurchased, Shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MoneyMarketFundsAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Money market investment carrying value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MoneyMarketFundsAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Money Market Funds, at Carrying Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TypeOfAdoptionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounting Standards Update [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Other comprehensive income (loss)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Other comprehensive income (loss), net of tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetirementPlanSponsorLocationDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Retirement Plan Sponsor Location [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_TreasuryStockValueAcquired_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Purchase of treasury shares, including excise tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_TreasuryStockValueAcquired_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Treasury stock value acquired.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_TreasuryStockValueAcquired_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Treasury Stock, Value, Acquired</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock option activity (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtDisclosureAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Disclosure [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Defined Benefit Plans And Other Postretirement Benefit Plans Disclosures [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedTranslationAdjustmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Foreign Currency Translation Adjustments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedTranslationAdjustmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accumulated Foreign Currency Adjustment Attributable to Parent [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Tax effect</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Tax effect</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other comprehensive income (loss), tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel">Other comprehensive income (loss), income tax benefit (provision)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_SupplementalPensionPlanOfTimkensteelCorporationMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Supplemental pension plan of TimkenSteel corporation.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_SupplementalPensionPlanOfTimkensteelCorporationMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Supplemental Pension Plan Of TimkenSteel Corporation [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_SupplementalPensionPlanOfTimkensteelCorporationMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Supplemental Plan</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_CurrentFiscalYearEndDate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current Fiscal Year End Date</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_CurrentFiscalYearEndDate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Current Fiscal Year End Date</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt Instrument [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Long-Term Debt Instruments [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_DefinedBenefitPlanOfRecognizedLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Defined Benefit Plan of Recognized Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_DefinedBenefitPlanOfRecognizedLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Defined benefit plan of recognized loss.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_DefinedBenefitPlanOfRecognizedLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Defined benefit plan of recognized loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_DefinedBenefitPlanOfRecognizedLoss_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Defined benefit plan of recognized loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentQuarterlyReport_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document Quarterly Report</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentQuarterlyReport_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Quarterly Report</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressStateOrProvince_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Address, State or Province</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressStateOrProvince_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address, State or Province</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentConvertibleThresholdConsecutiveTradingDays1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument, Convertible, Threshold Consecutive Trading Days</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentConvertibleThresholdConsecutiveTradingDays1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt Instrument, threshold consecutive trading days</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredFinanceCostsGross_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Issuance Costs, Gross</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredFinanceCostsGross_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Transaction costs, debt gross</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ComprehensiveIncomeNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Comprehensive Income (Loss), net of tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ComprehensiveIncomeNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Comprehensive Income (Loss), Net of Tax, Attributable to Parent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Incremental Common Shares Attributable to Share-based Payment Arrangements, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Incremental Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangements</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Dilutive effect of stock-based awards (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InventoryRawMaterials_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Inventory, Raw Materials, Gross</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InventoryRawMaterials_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Inventory, Raw Materials, Gross, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InventoryRawMaterials_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Raw materials</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountsPayableTradeCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accounts payable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountsPayableTradeCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounts Payable, Trade, Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock option activity</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PerformanceSharesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Performance Shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PerformanceSharesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Performance Shares [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInDeferredIncomeTaxes_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Deferred income taxes</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInDeferredIncomeTaxes_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase (Decrease) in Deferred Income Taxes</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_DefinedBenefitPlanTerminatedEffectiveDate_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Defined benefit plan terminated effective date.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_DefinedBenefitPlanTerminatedEffectiveDate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Defined Benefit Plan Terminated Effective Date</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_DefinedBenefitPlanTerminatedEffectiveDate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Expected annuity purchase year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_DefinedBenefitPlanTerminatedEffectiveDate_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Benefit plan terminated effective date</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Postretirement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Postretirement Benefits Plan [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsequentEventMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Subsequent Event</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsequentEventMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Subsequent Event [Member]</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpenseOperating_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Expense, Operating</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherAssetsNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Other Assets, Noncurrent, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherAssetsNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other non-current assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherAssetsNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Assets, Noncurrent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Antidilutive Securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Antidilutive Securities [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLossCarryforwardsLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Loss Carryforwards [Line Items]</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_IncrementalCommonSharesAttributableToShareBasedPaymentArrangementsSharesAssumedPurchasedWithPotentialProceeds_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Incremental common shares attributable to share based payment arrangements shares assumed purchased with potential proceeds.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StateAndLocalJurisdictionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">State and Local Jurisdiction [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StateAndLocalJurisdictionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">State and Local</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accumulated Other Comprehensive Income (Loss)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">AOCI Attributable to Parent [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_NameOfMajorCustomerDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Customer</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_NameOfMajorCustomerDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Customer [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TreasuryStockCommonShares_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Treasury Stock, Common, Shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TreasuryStockCommonShares_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Treasury shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodSharesTreasuryStockReissued_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Issuance of treasury shares (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodSharesTreasuryStockReissued_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stock Issued During Period, Shares, Treasury Stock Reissued</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Increase (Decrease) in Stockholders' Equity [Roll Forward]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase (Decrease) in Stockholders' Equity [Roll Forward]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Preferred Stock, Value, Issued, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Preferred Stock, Value, Issued, Beginning Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Preferred Stock, Value, Issued, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Preferred shares, without par value; authorized 10.0 million shares, none issued</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Preferred Stock, Value, Issued</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SellingGeneralAndAdministrativeExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Selling, General and Administrative Expense, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SellingGeneralAndAdministrativeExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Selling, general and administrative expenses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SellingGeneralAndAdministrativeExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Selling, General and Administrative Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair value of shares granted</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsCurrentAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsCurrentAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Assets, Current [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Segment Reporting [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesCurrentAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current Liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesCurrentAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Liabilities, Current [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringAndRelatedActivitiesDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Restructuring Charges</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringAndRelatedActivitiesDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restructuring and Related Activities Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_PensionCostandOtherPostretirementBenefitsCostReversalofCostExcludingServiceComponent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Pension and postretirement non-service benefit (income) loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_PensionCostandOtherPostretirementBenefitsCostReversalofCostExcludingServiceComponent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Pension Costand Other Postretirement Benefits Cost Reversalof Cost Excluding Service Component</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_PensionCostandOtherPostretirementBenefitsCostReversalofCostExcludingServiceComponent_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Pension Cost and Other Postretirement Benefits Cost (Reversal of Cost), Excluding Service Component</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Beginning balance (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Ending balance (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Shares, Outstanding</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountsReceivableNetCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Accounts Receivable, after Allowance for Credit Loss, Current, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountsReceivableNetCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounts Receivable, after Allowance for Credit Loss, Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountsReceivableNetCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accounts receivable, net of allowances (2025 - $2.2 million; 2024 - $1.5 million)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpenseAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Expense, Operating and Nonoperating [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedBenefitPlanServiceCost_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Service cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedBenefitPlanServiceCost_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Defined Benefit Plan, Service Cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InventoryWorkInProcess_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Work in process</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InventoryWorkInProcess_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Inventory, Work in Process, Gross</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_ProceedsFromGovernmentFunding_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Proceeds from government funding</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_ProceedsFromGovernmentFunding_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Proceeds from government funding.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_ProceedsFromGovernmentFunding_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds from Government Funding</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_InvestmentGainsOnPlanAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Investment gains on plan assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_InvestmentGainsOnPlanAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Investment Gains On Plan Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_InvestmentGainsOnPlanAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Investment gains on plan assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueTreasuryStockReissued_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Issuance of treasury shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueTreasuryStockReissued_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stock Issued During Period, Value, Treasury Stock Reissued</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesNoncurrentAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Non-Current Liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesNoncurrentAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Liabilities, Noncurrent [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfRestructuringReserveByTypeOfCostTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Restructuring Reserve</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfRestructuringReserveByTypeOfCostTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Restructuring Reserve by Type of Cost [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeExpenseNet_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedTotalLabel">Interest (income) expense, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeExpenseNet_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Interest (income) expense, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeExpenseNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Income (Expense), Operating</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeExpenseNet_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Interest (income) expense, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongtermDebtTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Term Debt, Type [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Weighted Average Number of Shares Outstanding, Basic, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Weighted average shares outstanding, basic (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Weighted Average Number of Shares Outstanding, Basic</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_SalesAndUseTaxRefund_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Sales and use taxes refund</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_SalesAndUseTaxRefund_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Sales and use tax refund</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_SalesAndUseTaxRefund_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Sales And Use Tax Refund</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_SalesAndUseTaxRefund_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Sales and use tax refund.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsequentEventsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Subsequent Events [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsequentEventsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Subsequent Events</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total debt</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Term Debt</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">APIC, Share-based Payment Arrangement, Increase for Cost Recognition, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock-based compensation expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">APIC, Share-Based Payment Arrangement, Increase for Cost Recognition</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedBenefitPlanActuarialGainLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedBenefitPlanActuarialGainLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Non cash gain (loss)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquity_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Beginning balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquity_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Ending balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquity_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Equity, Attributable to Parent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquity_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total Shareholders' Equity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsRemainderOfFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsRemainderOfFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Additional contributions expected to be made during remainder of fiscal year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeAndInterestExpenseDisclosureTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Income and Interest Expense Disclosure [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeAndInterestExpenseDisclosureTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Interest (income) Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementOfStockholdersEquityAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement of Stockholders' Equity [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_TimkensteelCorporationRetirementPlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">TimkenSteel corporation retirement plan.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_TimkensteelCorporationRetirementPlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">TimkenSteel Corporation Retirement Plan [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_TimkensteelCorporationRetirementPlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Salaried Plan</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TreasuryStockCommonMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Treasury Shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TreasuryStockCommonMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Treasury Stock, Common [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ForeignCurrencyTransactionGainLossBeforeTax_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Foreign currency exchange (gain) loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ForeignCurrencyTransactionGainLossBeforeTax_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Foreign Currency Transaction Gain (Loss), before Tax, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ForeignCurrencyTransactionGainLossBeforeTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Gain (Loss), Foreign Currency Transaction, before Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="country_US_lbl" xlink:role="http://www.xbrl.org/2003/role/label">UNITED STATES</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="country_US_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">United States of America</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Pension and Postretirement Liability Adjustments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentNameDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt Instrument, Name</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentNameDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument, Name [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherAssetsCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other current assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherAssetsCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Assets, Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_SpecialBarQualityBarsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Bar</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_SpecialBarQualityBarsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Special Bar Quality Bars [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_SpecialBarQualityBarsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Special Bar Quality Bars [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingCodmIndividualTitleAndPositionOrGroupOrCommitteeNameExtensibleEnumeration_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Segment Reporting, CODM, Individual Title and Position or Group Name [Extensible Enumeration]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CreditFacilityAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Credit Facility</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CreditFacilityAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Credit Facility [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CostOfGoodsAndServicesSold_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Cost of Goods and Services Sold, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CostOfGoodsAndServicesSold_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cost of products sold</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CostOfGoodsAndServicesSold_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cost of Product and Service Sold</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentRepaidPrincipal_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument, Repaid, Principal</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentRepaidPrincipal_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Company repaid principal amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TreasuryStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Treasury Stock, Value, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TreasuryStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Treasury Stock, Value, Beginning Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TreasuryStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Treasury Stock, Value, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TreasuryStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Treasury Stock, Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TreasuryStockValue_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Treasury shares - 2025 - 6.4 million; 2024 - 5.7 million</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GovernmentAssistanceTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Government Assistance [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ForeignCountryMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Foreign Tax Jurisdiction [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ForeignCountryMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Foreign</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PensionPlansDefinedBenefitMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Pension</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PensionPlansDefinedBenefitMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Pension Plan [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressCityOrTown_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Address, City or Town</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressCityOrTown_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address, City or Town</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NumberOfReportableSegments_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Number of Reportable Segments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NumberOfReportableSegments_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of reportable segments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_SecurityExchangeName_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Security Exchange Name</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_SecurityExchangeName_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Security Exchange Name</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CreditFacilityDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Credit Facility</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CreditFacilityDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Credit Facility [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Income (Loss) Before Income Taxes</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AntidilutiveSecuritiesNameDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Antidilutive Securities, Name</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AntidilutiveSecuritiesNameDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Antidilutive Securities, Name [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetirementPlanSponsorLocationAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Retirement Plan Sponsor Location [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_TimkensteelUKPensionSchemeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">TimkenSteel U.K. pension scheme.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_TimkensteelUKPensionSchemeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">TimkenSteel U.K. Pension Scheme [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_TimkensteelUKPensionSchemeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Pension Scheme</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InventoryNet_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total inventories, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InventoryNet_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Inventories, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InventoryNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Inventory, Net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Cash, cash equivalents, and restricted cash at beginning of period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Cash, Cash Equivalents, and Restricted Cash at End of Period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total cash, cash equivalents, and restricted cash shown in the Consolidated Statements of Cash Flows</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total cash, cash equivalents, and restricted cash shown in the Consolidated Statements of Cash Flows</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total Current Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Assets, Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllocatedShareBasedCompensationExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock-based compensation expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllocatedShareBasedCompensationExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Payment Arrangement, Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentPeriodEndDate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document Period End Date</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentPeriodEndDate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Period End Date</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherIncomeAndExpensesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Income and Expenses [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GovernmentAssistanceLiabilityCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Government Assistance, Liability, Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GovernmentAssistanceLiabilityCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Government funding liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_IndustrialMarketSectorMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Industrial</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_IndustrialMarketSectorMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Industrial Market Sector [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_IndustrialMarketSectorMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Industrial Market Sector [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementOfFinancialPositionAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement of Financial Position [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestrictedStockUnitsRSUMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Restricted Stock Units</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestrictedStockUnitsRSUMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restricted Stock Units (RSUs) [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_AutomotiveMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Automotive [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_AutomotiveMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Automotive [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_AutomotiveMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Automotive</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_IncrementalCommonSharesAttributableToShareBasedPaymentArrangementsSharesAssumedIssued_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Incremental Common Shares Attributable To Share Based Payment Arrangements Shares Assumed Issued</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_IncrementalCommonSharesAttributableToShareBasedPaymentArrangementsSharesAssumedIssued_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Incremental common Shares attributable to share based payment arrangements shares assumed Issued.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_IncrementalCommonSharesAttributableToShareBasedPaymentArrangementsSharesAssumedIssued_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Shares assumed issued</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Antidilutive Security, Excluded EPS Calculation [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other comprehensive income (loss), net of benefit (provision) for income taxes of none and $(0.1) million for the three months ended September 30, 2025 and 2024, and net of benefit (provision) for incomes taxes of $(0.3) million and $(0.1) million for the nine months ended September 30, 2025 and 2024</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Liabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total Liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Liabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherNonoperatingIncomeAndExpenseTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other (Income) Expense, Net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherNonoperatingIncomeAndExpenseTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Nonoperating Income and Expense [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ReclassificationFromAociCurrentPeriodBeforeTaxAttributableToParent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Reclassification from AOCI, Current Period, before Tax, Attributable to Parent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ReclassificationFromAociCurrentPeriodBeforeTaxAttributableToParent_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Amounts reclassified from accumulated other comprehensive income (loss), before income tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_PensionCostandOtherPostretirementBenefitsCostReversalofCostRemeasurement_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Pension Cost and Other Postretirement Benefits Cost (Reversal of Cost), Remeasurement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_PensionCostandOtherPostretirementBenefitsCostReversalofCostRemeasurement_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Pension Cost and Other Postretirement Benefits Cost Reversal of Cost Remeasurement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_PensionCostandOtherPostretirementBenefitsCostReversalofCostRemeasurement_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Total gain from remeasurement of benefit plans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_PensionCostandOtherPostretirementBenefitsCostReversalofCostRemeasurement_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Total loss from remeasurement of benefit plans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_PensionCostandOtherPostretirementBenefitsCostReversalofCostRemeasurement_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loss (gain) from remeasurement of benefit plans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NewAccountingPronouncementOrChangeInAccountingPrincipleDescription_lbl" xlink:role="http://www.xbrl.org/2003/role/label">New Accounting Pronouncement or Change in Accounting Principle, Description</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NewAccountingPronouncementOrChangeInAccountingPrincipleDescription_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">New accounting pronouncement description</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Expected return on plan assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Defined Benefit Plan, Expected Return (Loss) on Plan Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestrictedCash_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restricted Cash</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestrictedCash_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Restricted Cash</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Weighted average shares outstanding, diluted (in shares)</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GovernmentAssistanceTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Government Assistance [Text Block]</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityFileNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity File Number</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityFileNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Securities Act File Number</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DomesticPlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Domestic Plan [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DomesticPlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Domestic Plan</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_CoverAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cover [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred charges and prepaid expenses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Prepaid Expense and Other Assets, Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NumberOfOperatingSegments_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Number of Operating Segments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NumberOfOperatingSegments_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of operating segments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Segment Reporting Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Segment Reporting</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_DefinedBenefitPlanTermOfContract_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Defined benefit plan term of contract.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_DefinedBenefitPlanTermOfContract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Defined Benefit Plan Term Of Contract</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_DefinedBenefitPlanTermOfContract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Defined benefit plan term of contract</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GainsLossesOnExtinguishmentOfDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Gain (Loss) on Extinguishment of Debt, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GainsLossesOnExtinguishmentOfDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Gain (Loss) on Extinguishment of Debt</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GainsLossesOnExtinguishmentOfDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loss on extinguishment of debt</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GainsLossesOnExtinguishmentOfDebt_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Loss on extinguishment of debt</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringCharges_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Restructuring Charges, Total</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringCharges_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Restructuring charges</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringCharges_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restructuring Charges</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Adoption of New Accounting Standards</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">New Accounting Pronouncements, Policy [Policy Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_EnergyMarketSectorMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Energy</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_EnergyMarketSectorMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Energy Market Sector [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_EnergyMarketSectorMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Energy Market Sector [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GainLossOnDispositionOfAssets1_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Gain (Loss) on Disposition of Assets, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GainLossOnDispositionOfAssets1_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Loss (gain) on sale or disposal of assets, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GainLossOnDispositionOfAssets1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Gain (Loss) on Disposition of Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GainLossOnDispositionOfAssets1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loss (gain) on sale or disposal of assets, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ComprehensiveIncomeNoteTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accumulated Other Comprehensive Income (Loss)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ComprehensiveIncomeNoteTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Comprehensive Income (Loss) Note [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_TreasuryStockShareAcquired_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Purchase of treasury shares, including excise tax (in Shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_TreasuryStockShareAcquired_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Treasury stock, share, acquired.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_TreasuryStockShareAcquired_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Treasury Stock, Share, Acquired</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Pension and postretirement liability adjustments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Common Stock, Shares, Outstanding, Beginning Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Common Stock, Shares, Outstanding, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock, Shares, Outstanding</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common Stock, Shares outstanding</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiabilityCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current operating lease liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiabilityCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease, Liability, Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DepreciationDepletionAndAmortization_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Depreciation, Depletion and Amortization, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DepreciationDepletionAndAmortization_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Depreciation and amortization</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DepreciationDepletionAndAmortization_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Depreciation, Depletion and Amortization</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_GovernmentAssistanceCapitalFundings_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Government assistance capital fundings.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_GovernmentAssistanceCapitalFundings_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Government Assistance Capital Fundings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_GovernmentAssistanceCapitalFundings_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Government assistance capital fundings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Amortization of prior service cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Defined Benefit Plan, Amortization of Prior Service Cost (Credit)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentTransitionReport_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document Transition Report</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentTransitionReport_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Transition Report</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_OtherComprehensiveIncomeLossDeferralsBeforeTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Amounts deferred to accumulated other comprehensive income (loss),before income tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_OtherComprehensiveIncomeLossDeferralsBeforeTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Comprehensive Income Loss Deferrals Before Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_OtherComprehensiveIncomeLossDeferralsBeforeTax_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other comprehensive income loss deferrals before tax.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsForRepurchaseOfCommonStock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Payments for Repurchase of Common Stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsForRepurchaseOfCommonStock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Purchase of treasury shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsForRepurchaseOfCommonStock_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Purchase of treasury shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of (Benefit) Provision for Income Taxes</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accrued pension and postretirement costs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Liability, Defined Benefit Plan, Noncurrent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementOfCashFlowsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement of Cash Flows [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Earnings (Loss) Per Share</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_KristineCSyrvalinTradingArrangementCommonSaleMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Kristine C. Syrvalin Trading Arrangement Common Sale [Member]</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Investing Activities</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestPaid_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Paid, Including Capitalized Interest, Operating and Investing Activities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestPaid_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Interest Paid, Including Capitalized Interest, Operating and Investing Activities, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestPaid_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest paid</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NewAccountingPronouncementsAndChangesInAccountingPrinciplesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounting Standards Update and Change in Accounting Principle [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_OtherMarketSectorMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_OtherMarketSectorMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Market Sector [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_OtherMarketSectorMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other Market Sector [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromStockOptionsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Proceeds from exercise of stock options</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromStockOptionsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds from Stock Options Exercised</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTaxAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net Income (Loss) Available to Common Stockholders, Basic, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net income (loss), basic</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Net Income (Loss) Available to Common Stockholders, Basic</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LineOfCredit_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Long-term Line of Credit, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LineOfCredit_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Outstanding borrowings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LineOfCredit_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Term Line of Credit</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt Instrument</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedBenefitPlanInterestCost_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedBenefitPlanInterestCost_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Defined Benefit Plan, Interest Cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Payment Arrangement [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net Cash Provided (Used) by Investing Activities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash Provided by (Used in) Investing Activity, Including Discontinued Operation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_Security12bTitle_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Title of 12(b) Security</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_Security12bTitle_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Title of 12(b) Security</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share Repurchase Program, Remaining Authorized, Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock Repurchase Program, Remaining Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Income Tax Provision</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Tax Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_ManufacturedComponentsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Manufactured Components</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_ManufacturedComponentsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Manufactured Components [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_ManufacturedComponentsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Manufactured components.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherLiabilitiesNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Other Liabilities, Noncurrent, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherLiabilitiesNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other non-current liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherLiabilitiesNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Liabilities, Noncurrent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Changes in operating assets and liabilities:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxDisclosureAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Tax Disclosure [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdditionalPaidInCapitalMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Additional Paid-in Capital</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdditionalPaidInCapitalMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Additional Paid-in Capital [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_InvestmentLossesOnPlanAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Investment Losses On Plan Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_InvestmentLossesOnPlanAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Investment Losses On Plan Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_InvestmentLossesOnPlanAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Investment losses on plan assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="country_GB_lbl" xlink:role="http://www.xbrl.org/2003/role/label">UNITED KINGDOM</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="country_GB_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">United Kingdom</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_DefinedBenefitPlanContractExpirationDate_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Defined benefit plan contract expiration date.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_DefinedBenefitPlanContractExpirationDate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Defined Benefit Plan Contract Expiration Date</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_DefinedBenefitPlanContractExpirationDate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Defined benefit plan contract expiration date</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_StockRepurchaseProgramAuthorizedAmount1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share Repurchase Program, Authorized, Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_StockRepurchaseProgramAuthorizedAmount1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock Repurchase Program, Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">New Accounting Pronouncements Or Change In Accounting Principle [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">New Accounting Pronouncements or Change in Accounting Principle [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_TradingSymbol_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Trading Symbol</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_TradingSymbol_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Trading Symbol</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsequentEventTypeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Subsequent Event Type [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsequentEventTypeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Subsequent Event</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Financing Activities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_SalariesWagesAndBenefitsCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Salaries, wages and benefits</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_SalariesWagesAndBenefitsCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Salaries Wages And Benefits Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_SalariesWagesAndBenefitsCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Salaries wages and benefits current.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_NumberOfBargainingEmployees_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Number of Bargaining Employees</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_NumberOfBargainingEmployees_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Number of bargaining employees.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_NumberOfBargainingEmployees_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of bargaining employees in the contract</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_IncreaseDecreasInTheLiabilityOfIncreaseInTheDiscountRate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase Decreas in the Liability of Increase in the Discount Rate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_IncreaseDecreasInTheLiabilityOfIncreaseInTheDiscountRate_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Increase decreas in the liability of increase in the discount rate.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_IncreaseDecreasInTheLiabilityOfIncreaseInTheDiscountRate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Offset amount in the decrease of liability</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementEquityComponentsAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Equity Components</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementEquityComponentsAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Equity Components [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EquityComponentDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Equity Component</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EquityComponentDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Equity Component [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedBenefitPlanSettlementsBenefitObligation_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedBenefitPlanSettlementsBenefitObligation_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedBenefitPlanSettlementsBenefitObligation_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Settlements</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedBenefitPlanSettlementsBenefitObligation_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Defined benefit plan settlement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_MobileMarketSectorMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Mobile</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_MobileMarketSectorMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Mobile Market Sector [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_MobileMarketSectorMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Mobile Market Sector [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_MajorCustomersAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Customer</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_MajorCustomersAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Customer [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement of Comprehensive Income [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_SeamlessMechanicalTubingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Tube</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_SeamlessMechanicalTubingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Seamless Mechanical Tubing [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_SeamlessMechanicalTubingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Seamless Mechanical Tubing [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Common Stock, Value, Issued, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Common Stock, Value, Issued, Beginning Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Common Stock, Value, Issued, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock, Value, Issued</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common shares, without par value; authorized 200.0 million shares; issued 2025 - 48.2 million shares and 2024 - 48.2 million shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net income (loss), diluted</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Net Income (Loss) Available to Common Stockholders, Diluted</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxContingencyTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Tax Contingency [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ConvertibleNotesPayableCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current convertible notes, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ConvertibleNotesPayableCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Convertible Notes Payable, Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockSharesAuthorized_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Preferred shares, authorized (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockSharesAuthorized_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Preferred Stock, Shares Authorized</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfDebtTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Current and Non-current Debt</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfDebtTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Debt [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Shares surrendered for employee taxes on stock compensation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Payment, Tax Withholding, Share-Based Payment Arrangement</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RevenueFromContractWithCustomerTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Revenue from Contract with Customer [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityRegistrantName_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Registrant Name</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityRegistrantName_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Registrant Name</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityCommonStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Common Stock, Shares Outstanding</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accumulated other comprehensive income (loss)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accumulated Other Comprehensive Income (Loss), Net of Tax</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Shares granted</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Assets_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total Assets</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeStatementAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Statement [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetirementPlanNameDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Retirement Plan Name [Domain]</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareDiluted_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Diluted earnings (loss) per share</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_TimkensteelCorporationBargainingUnitPensionPlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">TimkenSteel corporation bargaining unit pension plan.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_TimkensteelCorporationBargainingUnitPensionPlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">TimkenSteel Corporation Bargaining Unit Pension Plan [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_TimkensteelCorporationBargainingUnitPensionPlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Bargaining Plan</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_CityAreaCode_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">City Area Code</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_CityAreaCode_lbl" xlink:role="http://www.xbrl.org/2003/role/label">City Area Code</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedBenefitPlanBenefitObligationIncreaseDecreaseForRemeasurementDueToSettlement_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Remeasurement due to Settlement</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Defined Benefit Plans Disclosures [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Restricted Cash and Cash Equivalents, Current, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restricted Cash and Cash Equivalent, Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Restricted cash reported in other current assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentFaceAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument, Face Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentFaceAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt Instrument, Face Amount</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_StockIssuedDuringPeriodSharesStockBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Stock issued during period, shares, stock-based compensation.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Defined Benefit Plan [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_MiscellaneousNonoperatingIncomeExpense_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Miscellaneous (income) expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_MiscellaneousNonoperatingIncomeExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Miscellaneous Nonoperating Income Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_MiscellaneousNonoperatingIncomeExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Miscellaneous Nonoperating Income (Expense)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_GovernmentFundReceived_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Government Fund Received</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="mtus_GovernmentFundReceived_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Government fund received,</link:label>
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  <xsd:element id="mtus_ProceedsFromGovernmentFunding" name="ProceedsFromGovernmentFunding" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="mtus_TreasuryStockShareAcquired" name="TreasuryStockShareAcquired" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="mtus_FutureAllocatedShareBasedCompensationExpense" name="FutureAllocatedShareBasedCompensationExpense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="mtus_GovernmentFundReceived" name="GovernmentFundReceived" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="mtus_SalesAndUseTaxRefund" name="SalesAndUseTaxRefund" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="mtus_ManufacturedComponentsMember" name="ManufacturedComponentsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="mtus_IncreaseDecreasInTheLiabilityOfIncreaseInTheDiscountRate" name="IncreaseDecreasInTheLiabilityOfIncreaseInTheDiscountRate" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="mtus_FourthAmendedCreditFacilityMember" name="FourthAmendedCreditFacilityMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="mtus_LineofCreditFacilityTentativeFutureCommitmentIncrease" name="LineofCreditFacilityTentativeFutureCommitmentIncrease" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="mtus_DefinedBenefitPlanContractExpirationDate" name="DefinedBenefitPlanContractExpirationDate" type="xbrli:dateItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="mtus_ConvertibleSeniorNotesdueTwentyTwentyOneMember" name="ConvertibleSeniorNotesdueTwentyTwentyOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="mtus_DefinedBenefitPlanOfRecognizedLoss" name="DefinedBenefitPlanOfRecognizedLoss" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="mtus_InvestmentLossesOnPlanAssets" name="InvestmentLossesOnPlanAssets" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="mtus_InvestmentGainsOnPlanAssets" name="InvestmentGainsOnPlanAssets" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="mtus_SalariesWagesAndBenefitsCurrent" name="SalariesWagesAndBenefitsCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="mtus_EnergyMarketSectorMember" name="EnergyMarketSectorMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="mtus_TimkensteelCorporationRetirementPlanMember" name="TimkensteelCorporationRetirementPlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="mtus_ContractLiabalitiesTotalated" name="ContractLiabalitiesTotalated" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="mtus_TimkensteelUKPensionSchemeMember" name="TimkensteelUKPensionSchemeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="mtus_MobileMarketSectorMember" name="MobileMarketSectorMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="mtus_AerospaceAndDefenseMember" name="AerospaceAndDefenseMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="mtus_OtherMarketSectorMember" name="OtherMarketSectorMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="mtus_SpecialBarQualityBarsMember" name="SpecialBarQualityBarsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="mtus_ConvertibleSeniorNotesDueTwentyTwentyFiveMember" name="ConvertibleSeniorNotesDueTwentyTwentyFiveMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="mtus_PensionAndOtherPostretirementBenefitsExpenseReversalOfExpenseNoncashExcludingMarkToMarketAdjustments" name="PensionAndOtherPostretirementBenefitsExpenseReversalOfExpenseNoncashExcludingMarkToMarketAdjustments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="mtus_DefinedBenefitPlanTermOfContract" name="DefinedBenefitPlanTermOfContract" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="mtus_MiscellaneousNonoperatingIncomeExpense" name="MiscellaneousNonoperatingIncomeExpense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="mtus_PensionCostAndOtherPostretirementBenefitsCostPlanGainOnAnnuitization" name="PensionCostAndOtherPostretirementBenefitsCostPlanGainOnAnnuitization" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="mtus_IndustrialMarketSectorMember" name="IndustrialMarketSectorMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="mtus_AutomotiveMember" name="AutomotiveMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
</xsd:schema>
