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<SEC-DOCUMENT>0000950138-05-001037.txt : 20051024
<SEC-HEADER>0000950138-05-001037.hdr.sgml : 20051024
<ACCEPTANCE-DATETIME>20051024174732
ACCESSION NUMBER:		0000950138-05-001037
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		2
CONFORMED PERIOD OF REPORT:	20050919
FILED AS OF DATE:		20051024
DATE AS OF CHANGE:		20051024

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MKS INSTRUMENTS INC
		CENTRAL INDEX KEY:			0001049502
		STANDARD INDUSTRIAL CLASSIFICATION:	INDUSTRIAL INSTRUMENTS FOR MEASUREMENT, DISPLAY, AND CONTROL [3823]
		IRS NUMBER:				042277512
		STATE OF INCORPORATION:			MA
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		90 INDUSTRIAL WAY
		CITY:			WILMINGTON
		STATE:			MA
		ZIP:			01887
		BUSINESS PHONE:		978-284-4000

	MAIL ADDRESS:	
		STREET 1:		90 INDUSTRIAL WAY
		CITY:			WILMINGTON
		STATE:			MA
		ZIP:			01887

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			EMERSON ELECTRIC CO
		CENTRAL INDEX KEY:			0000032604
		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTRONIC & OTHER ELECTRICAL EQUIPMENT (NO COMPUTER EQUIP) [3600]
		STATE OF INCORPORATION:			MO
		FISCAL YEAR END:			0930

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-23621
		FILM NUMBER:		051152878

	BUSINESS ADDRESS:	
		STREET 1:		8000 W FLORISSANT AVE
		STREET 2:		P O BOX 4100
		CITY:			ST LOUIS
		STATE:			MO
		ZIP:			63136
		BUSINESS PHONE:		3145532000

	MAIL ADDRESS:	
		STREET 1:		8000 W. FLORISSANT
		STREET 2:		P.O. BOX 4100
		CITY:			ST LOUIS
		STATE:			MO
		ZIP:			63136

	FORMER NAME:	
		FORMER CONFORMED NAME:	EMERSON ELECTRIC MANUFACTUING CO
		DATE OF NAME CHANGE:	19730710
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    <documentType>4</documentType>

    <periodOfReport>2005-09-19</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001049502</issuerCik>
        <issuerName>MKS INSTRUMENTS INC</issuerName>
        <issuerTradingSymbol>MKSI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000032604</rptOwnerCik>
            <rptOwnerName>EMERSON ELECTRIC CO</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>8000 W. FLORISSANT AVE.</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>ST. LOUIS</rptOwnerCity>
            <rptOwnerState>MO</rptOwnerState>
            <rptOwnerZipCode>63136</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2005-09-19</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>G</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>300000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>8663389</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Through a subsidiary.</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1065182</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Bona fide gift to the Emerson Charitable Trust.</footnote>
        <footnote id="F2">Price is not applicable to acquisitions or dispositions resulting from bona fide gifts.</footnote>
        <footnote id="F3">The reported securities are owned directly by Astec America, Inc. The Reporting Person is the ultimate parent company of
Astec America, Inc.</footnote>
    </footnotes>

    <remarks>See Exhibit 99 - Joint Filer Information</remarks>

    <ownerSignature>
        <signatureName>/s/ Harley M. Smith, Assistant Secretary of Emerson Electric Co.</signatureName>
        <signatureDate>2005-10-24</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Harley M. Smith, Secretary of Astec America, Inc.</signatureName>
        <signatureDate>2005-10-24</signatureDate>
    </ownerSignature>
</ownershipDocument>
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<DOCUMENT>
<TYPE>EX-99
<SEQUENCE>2
<FILENAME>exh99.htm
<DESCRIPTION>JOINT FILER INFORMATION
<TEXT>
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<TITLE> </TITLE>
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<p style=' margin-bottom:12pt; margin-top:0pt;text-align:right;'><b><font size=2>Exhibit 99</font></b></p>

<p style=' margin-bottom:12pt; margin-top:0pt;text-align:center;'><u><font size=2>Joint Filer Information</font></u></p>

<p style=' margin-bottom:12pt; margin-top:0pt;text-align:left;'><font size=2>Astec America, Inc., 5810 Van Allen Way, Carlsbad, California 92008, has designated Emerson Electric Co. as the &#147;Designated Filer&#148; for the purposes of the attached Form 4.</font></p>


<table border="0" cellspacing=0 cellpadding=0 width="456" style='border-collapse:collapse'>
    <tr >
        <td width="48" nowrap valign=top style='padding:0in 0in 12.0pt 0in; '>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:12pt'><font size=1>&nbsp;</font></p> </td>
        <td width="192" nowrap valign=top style='padding:0in 0in 12.0pt 0in; '>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=2>Issuer &amp; Ticker Symbol:</font></p> </td>
        <td  nowrap colspan="3" valign=top style='padding:0in 0in 12.0pt 0in; '>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=2>MKS Instruments, Inc. (MKSI)</font></p> </td> </tr>
    <tr >
        <td width="48" nowrap valign=top style='padding:0in 0in 12.0pt 0in; '>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:12pt'><font size=1>&nbsp;</font></p> </td>
        <td  nowrap colspan="2" valign=top style='padding:0in 0in 12.0pt 0in; '>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=2>Date of Event Requiring Statement:</font></p> </td>
        <td width="84" nowrap valign=top style='padding:0in 0in 12.0pt 0in; '>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=2>9/19/05</font></p> </td>
        <td  width="84">
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=1>&nbsp;</font></td> </tr>
    <tr>
        <td width="48" ></td>

        <td width="192" ></td>

        <td width="48" ></td>

        <td width="84" ></td>

        <td width="84" ></td> </tr> </table>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>


<table border="0" cellspacing=0 cellpadding=0 width="371" style='border-collapse:collapse'>
    <tr >
        <td width="96" nowrap valign=top >
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=2>Signature:</font></p> </td>
        <td  nowrap colspan="5" valign=top >
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><u><font size=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;/s/ Harley M. Smith&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</font></u></p> </td>
        <td  width="13">
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=1>&nbsp;</font></td> </tr>
    <tr >
        <td width="96" nowrap valign=top >
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0in'><font size=1>&nbsp;</font></p> </td>
        <td  nowrap colspan="6" valign=top >
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0in'><font size=2>By:  Harley M. Smith, Assistant Secretary</font></p> </td> </tr>
    <tr >
        <td  nowrap colspan="2" valign=top style='padding:0in 0in 12.0pt 0in; '>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:12pt'><font size=1>&nbsp;</font></p> </td>
        <td  nowrap colspan="2" valign=top style='padding:0in 0in 12.0pt 0in; '>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0in'><font size=2>of Emerson Electric Co.</font></p> </td>
        <td   colspan="3">
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=1>&nbsp;</font></td> </tr>
    <tr >
        <td width="96" nowrap valign=top >
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=2>Signature:</font></p> </td>
        <td  nowrap colspan="5" valign=top >
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><u><font size=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;/s/ Harley M. Smith&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</font></u></p> </td>
        <td  width="13">
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=1>&nbsp;</font></td> </tr>
    <tr >
        <td width="96" nowrap valign=top >
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0in'><font size=1>&nbsp;</font></p> </td>
        <td  nowrap colspan="4" valign=top >
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0in'><font size=2>By:  Harley M. Smith, Secretary</font></p> </td>
        <td   colspan="2">
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=1>&nbsp;</font></td> </tr>
    <tr >
        <td  nowrap colspan="2" valign=top style='padding:0in 0in 12.0pt 0in; '>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:12pt'><font size=1>&nbsp;</font></p> </td>
        <td width="161" nowrap valign=top style='padding:0in 0in 12.0pt 0in; '>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0in'><font size=2>of Astec America, Inc.</font></p> </td>
        <td   colspan="4">
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=1>&nbsp;</font></td> </tr>
    <tr>
        <td width="96" ></td>

        <td width="28" ></td>

        <td width="161" ></td>

        <td width="12" ></td>

        <td width="13" ></td>

        <td width="47" ></td>

        <td width="13" ></td> </tr> </table>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>


<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'>&nbsp;</p>



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