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                                                                    Exhibit 10.1

                                 AMENDMENT No. 5

                                       to

                   AMETEK 401(k) PLAN FOR ACQUIRED BUSINESSES


                  WHEREAS, there was adopted and made effective as of May 1,
1999, the AMETEK 401(k) Plan for Acquired Businesses (the "Acquired Businesses
Plan"); and

                  WHEREAS, Section 10.1 of the Plan provides that AMETEK, Inc.
("AMETEK") may amend the Plan at any time, and from time to time; and

                  WHEREAS, AMETEK now desires to amend the Plan in certain
respects;

                  NOW, THEREFORE, the Plan is hereby amended as follows:

         FIRST: Schedule I is hereby amended, to read in its entirety as
follows:


                                   "SCHEDULE I



                 Subsidiary/Division                            Employer Matching Contribution
                 -------------------                            ------------------------------
                                                             
       Aerospace Division (Costa Mesa Plant)                                   4%
       AMETEK Patriot Sensors Division (Michigan)                              3%
       AMETEK Aerospace Patriot Products                                       3%
            (California)
       AMETEK Patriot Sensors Division (Pennsylvania)                          3%
       (known as Drexelbrook Controls, Inc. until merged into
       Patriot on 1/12/00)"
       AMETEK National Controls Corporation Retirement                         5%
             Savings Plan
       AMETEK Prestolite Power & Switch Division (Ohio)                        3%
       AMETEK Lamb Electric Division (Michigan Plant)                          3%
       AMETEK Lamb Electric Division (Oklahoma Plant)                          3%
       AMETEK Lamb Electric Division (Alabama Plant)                           3%


         SECOND: The provisions of this Amendment No. 5 shall be effective as of
September 1, 2000.




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         IN WITNESS WHEREOF, AMETEK has caused these presents to be executed, in
its corporate name, by its duly authorized officer on this 17 day of August,
2000.

                                                AMETEK, Inc.

                                                By: /s/ Donna F. Winquist
                                                    -----------------------


Attest:

 /s/ Kathryn E. Londra
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