PROMISSORY NOTE $50,000 Dated: December 13, 1999 Principal Amount State of New Jersey FOR VALUE RECEIVED, the undersigned hereby promises to pay to the order of Campbell Steward, 65 Asbury Street, Topsfield, MA 01983, the sum of Fifty Thousand Dollars ($50,000), together with interest thereon at the rate of 10% per annum on the unpaid balance. Said sum shall be paid in the manner following: DUE IN FULL FEBRUARY 13, 2000 All payments shall be first applied to interest and the balance to principal. This note may be prepaid at any time, in whole or in part, without penalty. All prepayments shall be applied in reverse order of maturity. This note shall, at the option of the holder hereof, be immediately due and payable upon the failure to make any payment due hereunder within 30 days of its due date. Payments not made within ten (10) days of due date shall be subject to a late charge of 1% of said payment. All payments hereunder shall be made to such address as may from time to time be designated by any holder hereof. The undersigned corporation agrees to remain fully bound hereunder until this note shall be fully paid and waive demand, presentment and protest and all notices thereto and further agree to remain bound, notwithstanding any extension, renewal, modification, waiver, or other indulgence by any holder or upon the discharge or release of any obligor hereunder or to this note. No modification or indulgence by any holder hereof shall be binding unless in writing; and any indulgence on any one occasion shall not be an indulgence for any other or future occasion. Any modification or change of terms, hereunder granted by any holder hereof, shall be valid and binding upon the undersigned corporation, notwithstanding the acknowledgment of any of the undersigned. This note shall take effect as a sealed instrument and shall be construed, governed and enforced in accordance with the laws of the State first appearing at the head of this note. The undersigned hereby execute this note as principals and not as sureties. Signed in the presence of: /s/ [ILLEGIBLE] TECH LABORATORIES. INC. - ---------------------------- Borrower Witness /s/ Bernard M. Ciongoli - ---------------------------- ---------------------------- Witness Bernard M. Ciongoli, President For Tech Laboratories, Inc.