EXHIBIT 10(aa)

AMENDMENT NO. 3 TO AND WAIVER OF AMENDED AND RESTATED
REVOLVING CREDIT AND SECURITY AGREEMENT

AMENDMENT NO. 3 dated as of March 21, 2002, by and among MARLTON
TECHNOLOGIES, INC., a Pennsylvania corporation, successor to Marlton
Technologies, Inc., a New Jersey corporation ("Marlton"), and certain
subsidiaries executing this Amendment as Borrowers (together with Marlton,
collectively, the "Borrowers") and FIRST UNION NATIONAL BANK, a national banking
association, as Bank (the "Bank") and as Agent (the "Agent").

WHEREAS, the Borrowers, the Agent and the Banks entered into a certain
Amended and Restated Revolving Credit and Security Agreement dated as of January
21, 2000 (as amended on the date hereof and hereafter, the "Credit Agreement");
capitalized terms not otherwise defined herein having the meanings set forth in
the Credit Agreement; and

WHEREAS, the parties wish to amend certain provisions of the Credit
Agreement;

NOW THEREFORE, in consideration of the mutual agreements herein
contained, the parties hereto, intending to be legally bound, hereby agree as
follows, effective on the date first above written.

1. Definitions. Section 1.1 shall be amended to add the following:

(a) "Tangible Net Worth" means as of any date Net Worth
minus Intangibles.

2. Minimum Net Worth. Section 6.24 shall be amended to read in full as
follows:

SECTION 6.24 Minimum Tangible Net Worth. MTI will maintain
at the end of each fiscal quarter, commencing with the
fiscal quarter ending March 31, 2002, consolidated
Tangible Net Worth in an amount not less than $7,800,000.
Minimum Tangible Net Worth shall increase annually by 50%
of MTI's cumulative consolidated net income for the fiscal
years ending December 31, 2002 and December 31, 2003. For
purposes of determining the required minimum as aforesaid
(a) cumulative consolidated net income shall include
consolidated net income for entire fiscal years only and
shall be determined by reference to the financial
statements delivered under Section 6.1, and (b) a
consolidated net loss during any period shall be deemed to
be consolidated net income in the amount of zero.

3. Representations and Covenants. The Borrowers hereby represent,
warrant and certify that, assuming the effectiveness of Paragraph 6
of this Amendment: (a) all representations and warranties contained
in the Credit Agreement, including without limitation the schedules
thereto (updated as attached hereto), are true, correct and complete
on and as of the date hereof, (b) all covenants and agreements made
in the Credit Agreement have been complied with and fulfilled, (c)
no Default or Event of Default is in existence on the date hereof,
and (d) this Amendment has been duly authorized, executed and
delivered by each Borrower and is the legal, valid and binding
obligation of each of the Borrowers, enforceable in accordance with
its terms.

4. Ratification. Other than as specifically set forth herein, the
Borrowers hereby ratify and confirm the Credit Agreement and all
instruments and agreements relating thereto, and confirm that (a)
all of the foregoing remain in full force and effect, (b) each of
the foregoing is enforceable against the Borrowers in accordance
with its terms, and (c) Borrowers have no defenses to its
obligations or claims relative to the Credit Agreement.

5. Miscellaneous. Article IX of the Credit Agreement is incorporated
herein by reference and shall apply to this Amendment. Execution of
this Amendment shall not constitute an agreement by the Agent or any
Bank to execute any other amendment, waiver or modification of the
Credit Agreement. References to the Credit Agreement in any document
relating thereto shall be deemed to include this Amendment. This
Amendment may be executed in counterparts.

6. Effectiveness. This Amendment and Waiver shall be effective when the
parties have each received a fully executed copy of this Amendment
and Waiver.

REMAINDER OF PAGE INTENTIONALLY LEFT BLANK

IN WITNESS WHEREOF, Borrowers, the Agent and the Banks have caused this
Amendment to be duly executed and delivered as of the date and year first above
written.

MARLTON TECHNOLOGIES, INC.

By: /s/ ▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇▇▇
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Name: ▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇▇▇
Title: Chief Executive Officer

SPARKS EXHIBITS HOLDING CORPORATION

By: /s/ ▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇▇▇
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Name: ▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇▇▇
Title: Chief Executive Officer

SPARKS EXHIBITS & ENVIRONMENTS CORP.