THE CHASE MANHATTAN BANK
CHASE

                                 PROMISSORY NOTE


$270,000                                                         Melville, N.Y.
                                                        Date: December 22, 2000


     On March 22, 2001 (insert  specific date or "DEMAND"),  for value received,
the undersigned  hereby promises to pay to the order of THE CHASE MANHATTAN BANK
(the "Bank") at its offices at 395 N. Service Rd.,  Melville,  N.Y., Two Hundred
Seventy  Thousand and 00/100  DOLLARS  with  interest  payable on  _____________
(specific  date) and the _______  day of each  ______________  (quarter,  month,
etc.)  thereafter (and at maturity) at a per annum rate of 1/2% above the Bank's
Prime Rate (which shall be the rate of interest as is publicly  announced at the
Bank's principal office from time to time as its Prime Rate), adjusted as of the
date of each such change.  The  foregoing  rate shall be computed for the actual
number of days elapsed on the basis of a 360-day year,  but in no event shall be
higher than the maximum permitted under applicable law. Interest on any past due
amount,  whether at the due date thereof or by acceleration,  shall be paid at a
rate of four percent  (4%) per annum in excess of the above stated rate,  but in
no event  higher than the  maximum  permitted  under  applicable  law.  Time for
payment extended by law shall be included in the computation of interest.

     The undersigned  hereby grants to the Bank a lien on, security  interest in
and right of set-off  against all monies,  securities  and other property of the
undersigned and the proceeds  thereof now or hereafter  delivered to remain with
or in transit in any manner to the Bank, its  correspondents  or its agents from
or for the undersigned, whether for safekeeping,  custody, pledge, transmission,
collection  or for any other  purpose,  or coming  into  possession,  control or
custody of the Bank,  Chase  Securities Inc., or any other affiliate of the Bank
in any way,  and,  also,  any balance of any deposit  account and credits of the
undersigned  with, and any other claims of the  undersigned  against,  the Bank,
Chase  Securities  Inc., or any other affiliate of the Bank at any time existing
(all of which are collectively called the "Collateral"),  as collateral security
for the payment of this note and all other  liabilities  and  obligations now or
hereafter owed by the  undersigned to the Bank,  contracted  with or acquired by
the Bank,  whether  joint,  several,  direct,  indirect,  absolute,  contingent,
secured,   unsecured,   matured  or  unmatured   (all  of  which  are  hereafter
collectively called  "Liabilities"),  hereby authorizing the Bank at any time or
times,  without notice or demand,  to apply any such  Collateral or any proceeds
thereof to any of such  Liabilities in such amounts as it in its sole discretion
may select,  either  contingent,  unmatured or  otherwise  and whether any other
collateral security therefor is deemed adequate or not.  Undersigned  authorizes
the Bank to deliver to others a copy of this note as written notification of the
undersigned's  transfer  of a  security  interest  in the  Collateral.  The Bank
further  is  authorized  at any time or times,  without  demand or notice to the
undersigned,  to  transfer to or register in the name of its nominee or nominees
all or any part of the Collateral and to exercise any and all rights,  power and
privileges (except that prior to an Event of Default the Bank shall not have the
right  to vote or to  direct  the  voting  of any  Collateral).  The  collateral
security  and other  rights  described  herein shall be in addition to any other
collateral  security  described  in  any  separate  agreement  executed  by  the
undersigned.

     In the event of: default in the prompt payment of any Liabilities;  default
in any other  indebtedness of the undersigned  (which,  for the purposes of this
sentence, means the undersigned or any guarantor,  surety or endorser of, or any
person  or  entity  which  has  pledged  any  of its  property  to  secure,  any
Liabilities);  complete or partial  liquidation or suspension of any business of
the undersigned;  dissolution,  merger,  consolidation or  reorganization of the
undersigned;  death of or loss of  employment  by an individual or any member of
any partnership (if the undersigned is an individual or a partnership);  failure
to furnish any  financial  information  or to permit  inspection of any books or
records at the Bank's request;  a  representation,  warranty or statement of the
undersigned  proving  false in any  material  respect  when  made or  furnished;
general   assignment   for  the  benefit  of  creditors  or  insolvency  of  the
undersigned;  commencement  of any  proceeding  supplementary  to any  execution
relating to any judgment against the undersigned;  attachment,  distraint, levy,
execution or final judgment  against the  undersigned or against the property of
the  undersigned;  assignment  by the  undersigned  of any  equity in any of the
Collateral  without the written consent of the Bank;  appointment of a receiver,
conservator,  rehabilitator or similar officer for the  undersigned,  or for any
property of the undersigned; tax

                                      -1-
<PAGE>

assessment by the United States Government or any state or political subdivision
thereof against the  undersigned;  the taking of possession of, or assumption of
control over, all or any substantial  part of the property of the undersigned by
the United States  Government,  or any state or political  subdivision  thereof,
foreign  government (de facto or de jure) or any agency of any thereof;  calling
of a meeting of creditors,  assignment for the benefit of creditors or bulk sale
or notice thereof; any mortgage, pledge of or creation of a security interest in
any assets without the consent of the holder of this note;  filing of a petition
in bankruptcy,  commencement of any proceeding  under any bankruptcy or debtor's
law  (or  similar  law   analogous   in  purpose  or  effect)  for  the  relief,
reorganization,  composition,  extension,  arrangement or readjustment of any of
the obligations by or against the undersigned;  then, and in any of those events
(each, an "Event of Default"), all Liabilities,  although otherwise unmatured or
contingent,  shall forthwith become due and payable without notice or demand and
notwithstanding  anything  to the  contrary  contained  herein  or in any  other
instrument.  Further,  acceptance of any payments  shall not waive or affect any
prior demand or  acceleration of these  Liabilities,  and each such payment made
shall be applied first to the payment of accrued interest, then to the aggregate
unpaid  principal or otherwise as determined by the Bank in its sole discretion.
The undersigned hereby irrevocably  consents to the in personam  jurisdiction of
the  federal  and/or  state  courts  located  within  the State of New York over
controversies  arising  from or  relating  to this note or the  Liabilities  and
IRREVOCABLY WAIVES TRIAL BY JURY and the right to interpose any counterclaims or
offset of any nature in any such litigation. The undersigned further irrevocably
waives presentment, demand, protest, notice of dishonor and all other notices or
demands  of any  kind in  connection  with  this  note or any  Liabilities.  The
undersigned shall be jointly and severally liable hereon.

     The Bank may, at its option,  at any time when in the  judgment of the Bank
the  Collateral is inadequate or the Bank deems itself  insecure,  or upon or at
any time after the occurrence of an Event of Default, proceed to enforce payment
of the same and exercise any of or all the rights and remedies afforded the Bank
by the Uniform Commercial Code (the "Code") or otherwise  possessed by the Bank.
Any requirement of the Code for reasonable  notice to the  undersigned  shall be
deemed to have been complied with if such notice is mailed,  postage prepaid, to
the  undersigned  and such other  persons  entitled to notice,  at the addresses
shown on the  records  of the Bank at least  four (4) days  prior to the time of
sale, disposition or other event requiring notice under the Code.

     The undersigned  agrees to pay to the Bank, as soon as incurred,  all costs
and  expenses  incidental  to  the  care,  preservation,   processing,  sale  or
collection of or  realization  upon any of or all the  Collateral or incurred in
connection  with the  enforcement  or  collection  of this  note,  or in any way
relating to the rights of the Bank  hereunder,  including  reasonable  inside or
outside  counsel  fees and  expenses.  Each and every  right and  remedy  hereby
granted  to the  Bank  or  allowed  to it by law  shall  be  cumulative  and not
exclusive  and each may be  exercised by the Bank from time to time and as often
as may be necessary.  The  undersigned  shall have the sole  responsibility  for
notifying the Bank in writing that the  undersigned  wishes to take advantage of
any  redemption,  conversion  or other  similar right with respect to any of the
Collateral.  The Bank may  release  any  party  (including  any  partner  or any
undersigned)  without  notice to any of the  undersigned,  whether as co-makers,
endorsers,  guarantors,  sureties,  assigns or otherwise,  without affecting the
liability  of any of the  undersigned  hereof or any partner of any  undersigned
hereof.

     Upon any transfer of this note,  the  undersigned  hereby waiving notice of
any such  transfer,  the Bank may deliver the  Collateral or any part thereof to
the transferee who shall  thereupon  become vested with all the rights herein or
under  applicable law given to the Bank with respect  thereto and the Bank shall
thereafter  forever be  relieved  and fully  discharged  from any  liability  or
responsibility in the matter;  but the Bank shall retain all rights hereby given
to it with respect to any  Liabilities  and  Collateral not so  transferred.  No
modification  or waiver of any of the provisions of this note shall be effective
unless in writing, signed by the Bank, and only to the extent therein set forth;
nor shall any such waiver be  applicable  except in the  specific  instance  for
which given. This agreement sets forth the entire  understanding of the parties,
and the undersigned  acknowledges that no oral or other agreements,  conditions,
promises,  understandings,  representations or warranties exist in regard to the
obligations hereunder, except those specifically set forth herein.

     If the undersigned is a partnership,  the agreement  herein contained shall
remain in force and applicable,  notwithstanding  any changes in the individuals
composing  the  partnership  or any release of any partner or partners and their
partners  shall not  thereby be  released  from any  liability.  If this note is
signed by more than one party, the terms  "undersigned",  as used herein,  shall
include the "undersigned and each of them" and each undertaking herein contained
shall be their joint and several  undertaking,  provided,  however,  that in the
phrases "of the undersigned",  "by the undersigned",  "against the undersigned",
"for the undersigned", "to the undersigned" and

                                      -2-
<PAGE>

" on the undersigned", the term "undersigned" shall mean the "undersigned or any
of them";  and the Bank may release or exchange any of the Collateral  belonging
to any of the parties  hereto and it may renew or extend any of the  liabilities
of any of them and may make  additional  advances or extensions of credit to any
of them or release or fail to set off any deposit  account or credit any of them
or grant  other  indulgences  to any of them,  all from time to time,  before or
after maturity  hereof,  with or without further notice to or assent from any of
the other parties hereto.  Each reference  herein to the Bank shall be deemed to
include its  successors,  endorsees and assigns,  in whose favor the  provisions
hereof  shall also inure.  Each  reference  herein to the  undersigned  shall be
deemed to include the heirs, executors,  administrators,  legal representatives,
successors  and  assigns of the  undersigned,  all of whom shall be bound by the
provisions hereof.

     The  provisions  of this note shall be construed  and  interpreted  and all
rights and obligations  hereunder  determined in accordance with the laws of the
State of New York, and, as to interest rates, applicable Federal law.

______________________________          /s/Vincent DiSpigno
                                        PWR Systems, Inc.
Address:______________________          Address: 3512 Veterans Memorial Highway
                                                 Bohemia, NY 11716