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                                                                   EXHIBIT 10.63

                              THIRTEENTH AMENDMENT
                           DATED AS OF JANUARY 6, 2004
                                       TO
                           RECEIVABLES SALE AGREEMENT
                           DATED AS OF OCTOBER 1, 1999

         THIS THIRTEENTH AMENDMENT (the "Amendment"), dated as of January 6,
2004, is entered into among Ametek Receivables Corp. (the "Seller"), Ametek,
Inc. (the "Initial Collection Agent"), Amsterdam Funding Corporation, a Delaware
corporation ("Amsterdam"), ABN AMRO Bank N.V., as Amsterdam's program letter of
credit provider (the "Enhancer"), the Liquidity Provider listed on the signature
page hereof (the "Liquidity Provider") and ABN AMRO Bank N.V., as agent for
Amsterdam, the Enhancer and the Liquidity Provider (the "Agent").

                                   WITNESSETH:

         WHEREAS, the Seller, Initial Collection Agent, Amsterdam, Enhancer,
Liquidity Provider and Agent have heretofore executed and delivered a
Receivables Sale Agreement, dated as of October 1, 1999 (as amended,
supplemented or otherwise modified through the date hereof, the "Sale
Agreement"),

         WHEREAS, the parties hereto desire to amend the Sale Agreement as
provided herein;

         NOW, THEREFORE, for good and valuable consideration, the receipt and
adequacy of which are hereby acknowledged, the parties hereto hereby agree that
the Sale Agreement shall be and is hereby amended as follows:

         Section 1. Upon execution by the parties hereto in the space provided
for that purpose below, the Sale Agreement shall be, and it hereby is, amended
as follows:

                  (a)      The date "January 6, 2004" appearing in clause (d) of
         the defined term "Liquidity Termination Date" appearing in Schedule I
         of the Sale Agreement is deleted and replaced with the date "December
         21, 2004."

                  (b)      The date "January 6, 2004" appearing in clause
         (c)(ii) of the defined term "Termination Date" appearing in Schedule I
         of the Sale Agreement is deleted and replaced with the date "December
         21, 2004.""

         Section 2. To induce the Agent and the Purchasers to enter into this
Amendment, the Seller and Initial Collection Agent represent and warrant to the
Agent and the Purchasers that: (a) the representations and warranties contained
in the Transaction Documents, are true and correct in all material respects as
of the date hereof with the same effect as though made on the date hereof (it
being understood and agreed that any representation or warranty which by its
terms is made as of a specified date shall be required to be true and correct in
all material

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respects only as of such specified date); (b) no Potential Termination Event
exists; (c) this Amendment has been duly authorized by all necessary corporate
proceedings and duly executed and delivered by each of the Seller and the
Initial Collection Agent, and the Sale Agreement, as amended by this Amendment,
and each of the other Transaction Documents are the legal, valid and binding
obligations of the Seller and the Initial Collection Agent, enforceable against
the Seller and the Initial Collection Agent in accordance with their respective
terms, except as enforceability may be limited by bankruptcy, insolvency or
other similar laws of general application affecting the enforcement of
creditors' rights or by general principles of equity; and (d) no consent,
approval, authorization, order, registration or qualification with any
governmental authority is required for, and in the absence of which would
adversely effect, the legal and valid execution and delivery or performance by
the Seller or the Initial Collection Agent of this Amendment or the performance
by the Seller or the Initial Collection Agent of the Sale Agreement, as amended
by this Amendment, or any other Transaction Document to which they are a party.

         Section 3. This Amendment may be executed in any number of counterparts
and by the different parties on separate counterparts and each such counterpart
shall be deemed to be an original, but all such counterparts shall together
constitute but one and the same Amendment.

         Section 4. Except as specifically provided above, the Sale Agreement
and the other Transaction Documents shall remain in full force and effect and
are hereby ratified and confirmed in all respects. The execution, delivery, and
effectiveness of this Amendment shall not operate as a waiver of any right,
power, or remedy of any Agent or any Purchaser under the Sale Agreement or any
of the other Transaction Documents, nor constitute a waiver or modification of
any provision of any of the other Transaction Documents. All defined terms used
herein and not defined herein shall have the same meaning herein as in the Sale
Agreement. The Seller agrees to pay on demand all costs and expenses (including
reasonable fees and expenses of counsel) of or incurred by the Agent and each
Purchaser Agent in connection with the negotiation, preparation, execution and
delivery of this Amendment.

         Section 5. This Amendment and the rights and obligations of the parties
hereunder shall be construed in accordance with and be governed by the law of
the State of New York.

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         IN WITNESS WHEREOF, the parties have caused this Amendment to be
executed and delivered by their duly authorized officers as of the date first
above written.

                                       ABN AMRO BANK N.V., as the Agent, as the
                                          Liquidity Provider and as the Enhancer

                                       By: /s/ Patricia Luken
                                          Title: Group Vice President

                                       By: /s/ Therese M. Gremley
                                          Title: Vice President

                                       AMSTERDAM FUNDING CORPORATION

                                       By: /s/ Bernard J. Angelo
                                          Title: Vice President

                                       METEK RECEIVABLES CORP.

                                       By: /s/ Deirdre D. Saunders
                                          Title: Treasurer

                                       AMETEK, INC.

                                       By: /s/ Deirdre D. Saunders
                                          Title: VP & Treasurer

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