EXHIBIT 6

                                FOURTH AMENDMENT

                                       TO

                      AMENDED AND RESTATED CREDIT AGREEMENT

         FOURTH AMENDMENT, dated as of January 5, 1996 (the "Amendment"), to the
Amended and Restated  Credit  Agreement,  dated as of April 12, 1995,  among NAI
Technologies,  Inc., a New York corporation (the  "Borrower"),  Chemical Bank, a
New York  banking  corporation  ("Chemical"),  The Bank of New York,  a New York
banking corporation ("BNY"), and each of the other financial  institutions which
from time to time becomes  party  thereto  (together  with Chemical and BNY, the
"Banks"),  BNY, as administrative  agent (in such capacity,  the "Administrative
Agent") and Chemical,  as collateral  agent (in such capacity,  the  "Collateral
Agent").

                               W I T N E S E T H :

         WHEREAS,  the Borrower,  the Banks,  the  Administrative  Agent and the
Collateral  Agent are  parties  to that  certain  Amended  and  Restated  Credit
Agreement,  dated as of April 12, 1995 (as amended by certain amendments,  dated
as of August 14,  1995,  October  13,  1995 and  November  6, 1995,  the "Credit
Agreement");

         WHEREAS,  unless otherwise defined herein,  terms defined in the Credit
Agreement and used herein are used herein as therein defined;

         WHEREAS,  Charles S. Holmes has purchased $2 million of 12% Convertible
Subordinated  Promissory  Notes  issued by the  Borrower,  and has  advised  the
Borrower that he or his designee intends to purchase an additional $1 million in
12% Convertible Subordinated Notes on or before February 15, 1996; and

         WHEREAS,  in consideration of the proposed purchase of an additional $1
million  in  12%  Convertible  Subordinated  Notes  and at  the  request  of the
Borrower, the Banks have agreed to consent to the extension of the Maturity Date
to February 15, 1996 on the terms hereinafter set forth.

         Accordingly, the parties hereto hereby agree as follows:

         SECTION 1. AMENDMENT TO ARTICLE I. Article I of the Credit Agreement is
hereby amended (a) by amending the definition of "Maturity Date" in its entirety
as follows:

         "Maturity Date" shall mean February 15, 1996.

and (b) by amending the definition of  "Projections" to substitute "the Maturity
Date" for the date provided therein.

         SECTION 2. AMENDMENT TO ARTICLE IX. Article IX of the Credit  Agreement
is  hereby  amended  by  amending  Section  9.05  thereof  to add the  words "or
financial  advisor" (x) after the words "any other counsel" in the parenthetical
clause of such Section and (y)







after the words "any  counsel" in the last clause of the first  sentence of such
Section.

         SECTION 3.  CONFIRMATION  OF LIENS.  The Borrower hereby confirms that,
pursuant to the terms of the Credit  Agreement and the Security  Documents,  the
Borrower and the  Guarantors  have  granted  Liens on all of their assets to the
Collateral  Agent for the  benefit of the Banks.  The  Borrower  hereby  further
confirms that it will not and will not permit its Subsidiaries to incur, create,
assume or suffer to exist any Lien on any property or assets,  income or profits
of the Borrower or any of its Subsidiaries other than those permitted by Section
6.01 of the Credit Agreement, and any such granting of any such Lien in favor of
any third person,  including the holders of the  Subordinated  Indebtedness  (as
hereinafter  defined)  shall  constitute  an Event of  Default  under the Credit
Agreement.  Nothing  contained herein shall constitute a release or modification
of any Lien in favor of the  Collateral  Agent and the  Banks in any  Collateral
which constitutes security for any of the Obligations.

         SECTION 4.  CONDITIONS TO  EFFECTIVENESS.  This Amendment  shall become
effective as of the date hereof (the "Effective Date") when all of the following
shall have occurred:

          (a) The Banks shall have each received counterparts of this Amendment,
     duly executed by the Borrower;

          (b) The Borrower  shall have executed and  delivered  amended Notes to
     each of the Banks, in substantially the form of Exhibit A hereto;

          (c) The Borrower shall have received an additional  $1,000,000 in cash
     from  Charles  Holmes  on or  before  December  P such  that the  total 12%
     Convertible  Subordinated Notes purchased by Holmes from the Borrower is in
     the aggregate principal amount of $2,000,000;

          (d) The  Borrower  shall be in  compliance  with all of the  terms and
     provisions  set forth in the Credit  Agreement to be observed and performed
     and,  after giving effect to this  Amendment,  no Event of Default or event
     which  with the  giving  of  notice or the  passage  of time or both  would
     constitute an Event of Default shall have occurred and be continuing; and

          (e) All representations  and warranties  contained in Section 3 of the
     Credit  Agreement and the other Loan Documents shall be true and correct in
     all material respects on and as of the Effective Date, except to the extent
     that such  representations  and warranties  expressly  relate to an earlier
     date.

         SECTION 5.  RATIFICATION.  Except to the  extent  hereby  amended,  the
Credit  Agreement  remains in full force and effect and is hereby  ratified  and
affirmed. References in the Loan Documents

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to the Credit  Agreement  shall mean such document as amended by this Amendment,
as the same may be further amended, supplemented or otherwise modified from time
to time.

         SECTION 6. COSTS AND EXPENSES.  All out-of-pocket  expenses incurred by
the Banks,  including the reasonable fees and  disbursements of Zalkin,  Rodin &
Goodman  LLP,  special  counsel  for the  Agents  and  the  Banks,  incurred  in
connection  with the negotiation and preparation of this Amendment shall be paid
by the  Borrower  as  provided  in  Section  9.05 of the Credit  Agreement.  The
Borrower  hereby  confirms that the Borrower shall be obligated to reimburse the
Banks'  reasonable  expenses incurred in the retention of a financial advisor to
the Banks in connection with the  administration  of the Loans or the protection
or enforcement of the Banks' rights in connection therewith.

         SECTION 7.  REFERENCES.  This Amendment  shall be limited  precisely as
written and shall not be deemed (a) to be a consent  granted  pursuant  to, or a
waiver or modification  of, any other term or condition of the Credit  Agreement
or any of the instruments or agreements  referred to therein or (b) to prejudice
any right or rights  which the  Administrative  Agent,  Collateral  Agent or the
Banks may now have or have in the future under or in connection  with the Credit
Agreement or the Loan Documents or any of the instruments or agreements referred
to therein.

         SECTION 8.  APPLICABLE  LAW.  THIS  AMENDMENT  SHALL IN ALL RESPECTS BE
CONSTRUED IN  ACCORDANCE  WITH AND GOVERNED BY THE LAWS OF THE STATE OF NEW YORK
APPLICABLE TO CONTRACTS MADE AND TO BE PERFORMED WHOLLY WITHIN SUCH STATE.

         SECTION 9.  HEADINGS.  Section  headings in this Amendment are included
herein for convenience of reference only and are not to affect the  construction
of, or to be taken into consideration in interpreting, this Amendment.

         SECTION 10. INTEGRATION. This Amendment represents the entire agreement
of the parties hereto with respect to the amendment of the Credit  Agreement and
the terms of any letters and other documentation entered into among the Borrower
and any Bank or the  Administrative  Agent or the Collateral  Agent prior to the
execution  of  this  Amendment  which  relate  to the  amendment  of the  Credit
Agreement shall be replaced by the terms of this Amendment.

         SECTION 11.  EXECUTION IN  COUNTERPARTS.  This Second  Amendment may be
executed  in any  number of  counterparts,  each of which  shall  constitute  an
original,  but all of which taken  together  shall  constitute  one and the same
instrument.

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         IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
duly  executed  and  delivered  in New York,  New York by their  proper and duly
authorized officers as of the day and year first above written.

                                    NAI TECHNOLOGIES, INC.

                                    By: /s/ Richard A. Schneider
                                       _______________________________
                                       Title: Executive Vice President

                                    THE BANK OF NEW YORK
                                    AS ADMINISTRATIVE AGENT AND AS A BANK

                                    By: /s/ Richard Maybaum
                                       _______________________________
                                       Vice President

                                    CHEMICAL BANK

                                    AS COLLATERAL AGENT AND AS A BANK

                                    By: /s/ Kathy A. Duncan
                                       _______________________________
                                       Vice President

Consented to as of this
5th day of January, 1996

NAI TECHNOLOGIES - SYSTEMS DIVISION CORPORATION

By: /s/ Richard A. Schneider
   _______________________
   Title: Secretary

WILCOM, INC.

By: /s/ Richard A. Schneider
   _______________________
   Title: Secretary

ARATHON, V.I., INC.

By: /s/ Richard A. Schneider
   _______________________
   Title: Secretary

CODAR TECHNOLOGY, INC.

By: /s/ Richard A. Schneider
   _______________________
   Title: Secretary

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