AMENDMENT TO PROMISSORY NOTE DATED MAY 6, 1998

                                                               Exhibit 10.3B

                           AMENDMENT TO PROMISSORY
                           NOTE DATED MAY 6, 1998

      THIS AMENDMENT is dated as of December 14, 2001 between Xxxxx X.
Xxxxxx ("Xxxxxx") and Intelligent Controls, Inc. (the "Company").

      WHEREAS, Xxxxxx and the Company are parties to that certain Employee
Restricted Stock Purchase Agreement dated as of May 1, 1998; and pursuant
to
that Agreement Xxxxxx executed a Promissory Note dated May 6, 1998 in favor
of the Company, in the principal amount of $1,332,500 (the "Note");

      WHEREAS, the Note by its terms is due and payable upon demand after
May 6, 2003; and

      WHEREAS, the Company has offered to extend the maturity date of the
Note by an additional three years;

      NOW, THEREFORE, it is hereby agreed that the maturity date of the
Note
shall be extended by three years; that, accordingly, the second paragraph
of
the Note shall be deemed amended to read in its entirety as follows:

         Said principal sum and interest thereon shall be due and payable on
         demand on or after May 6, 2006.

that all other provisions of the Note shall remain in full force and
effect,
without change; and that this amendment shall not be deemed a novation of
the Note.

      IN WITNESS WHERE OF, this amendment has been duly executed by the
parties as of the date first stated above.

INTELLIGENT CONTROLS, INC.

By:  /s  Xxxxxxx X. Xxx                /s Xxxxx X. Xxxxxx
     ----------------------------      ------------------
     Xxxxxxx X. Xxx, Chairman of       XXXXX X. XXXXXX
     The Compensation Committee