EXHIBIT 10.6

                                SECOND AMENDMENT
                                       TO
                     AMENDED AND RESTATED CREDIT AGREEMENT


                  SECOND   AMENDMENT,   dated  as  of  October   13,  1995  (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 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 that  certain  First
Amendment to Amended and Restated Credit Agreement, dated as of August 14, 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,  the  Borrower  and Charles  Holmes  ('Holmes')  have
reached  an  agreement  whereby  Holmes  will  make  a  $1,000,000  subordinated
unsecured loan to the Borrower in exchange for certain consideration;

                  WHEREAS,  the Borrower has  requested a limited  waiver of the
financial  covenant  set forth in Section 6.16 of the Credit  Agreement  for the
periods provided herein; and

                  WHEREAS,  the Borrower has requested and the Banks have agreed
to consent to the  incurrence  of such  subordinated  indebtedness  and to waive
compliance  with  the  financial   covenant  referred  to  above  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 by adding the following defined term to Section 1.01
thereof:

         'Second  Amendment' shall mean the Second Amendment dated as of October
         13, 1995 to the Agreement.

                  Section 2.  Amendments  to Article V.  Article V of the Credit
Agreement is hereby amended by adding the following sections at the end thereof:







         Section 5.16.  Delivery of Certificate.  Within five days after the end
         of each  month,  furnish  each of the  Banks  with a  certificate  of a
         Financial  Officer  certifying that neither the Borrower nor any of the
         Guarantors  have sold any Inventory,  fixtures or equipment for amounts
         less than 90% of the book value of such  assets  during  the  preceding
         month.

         Section  5.17.  Additional  Subordinated  Note.  In the event  that the
         Borrower seeks to obtain  $2,000,000 of the  Subordinated  Indebtedness
         permitted  by  Section  6.03(vi)  hereof,  cause  the  promissory  note
         delivered to the Subordinated Lender thereof to be in substantially the
         form of note annexed as Exhibit A to the Second Amendment.

                  Section 3.  Clarification  of Section  6.02.  For  purposes of
clarifying the provisions of Section 6.02, it is understood and agreed among the
parties  hereto that the sale of  Inventory,  fixtures and equipment for amounts
equal to or in excess of 90% of the book value of such assets would constitute a
sale in the  ordinary  course of  business,  and that a sale of such  assets for
amounts  below 90% of the book value of such assets would not  constitute a sale
in the ordinary course of business.

                  Section 4.  Amendments to Article VI. Article VI of the Credit
Agreement is hereby  amended by (a) amending  Section 6.03 thereof to delete the
word  'and'  prior  to  clause  (v) and to add  the  following  language  at the
conclusion of such Section just prior to the period:

         ; and (vi) Indebtedness of the Borrower to Charles Holmes or any of his
         Affiliates (the  'Subordinated  Lender') in an aggregate  amount not to
         exceed $3,000,000 (the 'Subordinated Indebtedness'), which Indebtedness
         shall be  subordinate in right of payment to the  Indebtedness  owed to
         the Bank under this Agreement.

and (b) to add the following section at the end thereof:

         Section  6.18.  Use  of  Proceeds  of  Subordinated  Indebtedness.  The
         Borrower  will  not,  and will not  permit  its  Subsidiaries  to,  use
         proceeds  of the  Subordinated  Indebtedness  for  purposes of mergers,
         acquisitions,  joint ventures or other business combinations.  Any such
         use of the proceeds of the Subordinated  Indebtedness  shall constitute
         an Event of Default under the Agreement.

                  Section  5.  Limited  Waiver  of  Section  6.16;  Consolidated
Tangible Net Worth.  Compliance with the financial covenant set forth in Section
6.16 of the Credit  Agreement  is hereby  waived  for the period  August 1, 1995
through December 15, 1995;  provided,  that the Consolidated  Tangible Net Worth
shall not be less than $1,000,000.

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                  Section 6. 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  (including  the  provisions of Section 2
hereof) 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 7. Representations and Warranties. The representations
and  warranties  set forth in  Section 3 of the  Credit  Agreement  are true and
correct in all  material  respects on and as of the date  hereof,  except to the
extent that such  representations and warranties  expressly relate to an earlier
date. As of the Effective  Date, and after giving effect to this  Amendment,  no
Event of Default,  or an event with which the giving of notice or the passage of
time, or both, would constitute an Event of Default, exists.

                  Section 8.  Counterparts.  This Amendment may be executed
in any number of counterparts, each of which shall constitute an
original and all of which when taken together shall constitute one
and the same instrument.

                  Section 9. 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 received $1,000,000
         in cash in respect of Subordinated Indebtedness; and

                           (c) The Banks shall have received a copy of the fully
         executed  promissory note of the Borrower to the Subordinated Lender in
         the form of Exhibit A hereto.

                  Section 10. 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 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.


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                  Section 11. Costs and  Expenses.  All  out-of-pocket  expenses
incurred  by the Banks,  including  the  reasonable  fees and  disbursements  of
Zalkin,  Rodin & Goodman LLP, counsel to the Banks,  incurred in connection with
the  negotiation and preparation of this Amendment shall be paid by the Borrower
as provided in  Subsection  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  12.  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  13.  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 14.  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 15. 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 16. 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.

                  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___________________________
                                            Title:

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                                          THE BANK OF NEW YORK
                                          as Administrative Agent and as a Bank

                                          By:___________________________
                                             Vice President

                                          CHEMICAL BANK
                                          as Collateral Agent and as a Bank

                                          By:___________________________
                                             Vice President
Consented to as of this
13th day of October, 1995

NAI TECHNOLOGIES - SYSTEMS DIVISION CORPORATION

By:_______________________
   Title:

WILCOM, INC.

By:_______________________
   Title:

ARATHON, V.I., INC.

By:_______________________
   Title:

CODAR TECHNOLOGY, INC.

By:_______________________
   Title:

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