Exhibit 10.4



                          MASTER REVOLVING CREDIT NOTE



DATE:     April  24,  2006

MAKER:    International  Test  Systems,  Inc.

PAYEE:    Carey  G.  Birmingham.

PLACE  FOR  PAYMENT:   20022  Creek  Farm,  San  Antonio,  Texas  78259

PRINCIPAL  AMOUNT:     Fifty  Thousand  and  No/100  Dollars  ($50,000.00)

ANNUAL  INTEREST  RATE  ON  UNPAID  PRINCIPAL  FROM  DATE:  Eight  percent (8%)

ANNUAL  INTEREST  RATE  ON  MATURED,  UNPAID  AMOUNTS:      Eight  percent (8%)

TERMS  OF  PAYMENT  (PRINCIPAL  AND  INTEREST):

     Interest,  if  any,  on  any unpaid principal shall be due on the fifteenth
(15th)  of each month.   All unpaid principal and interest is due and payable on
December  31,  2006.

     The  unpaid  principal  balance, including any unpaid and accrued interest,
shall  at  no  time  exceed  the  sum  of  Fifty  Thousand  and  No/100  Dollars
($50,000.00).  The  unpaid  principal  balance of this note at any time shall be
the  total  amounts  loaned  or  advanced hereunder by Payee, less the amount of
payments or prepayments of principal made hereon by or for the account of Maker.
It is contemplated that by reason of prepayments hereon, there may be times when
no  indebtedness  is  due  hereunder; but notwithstanding such occurrences, this
note  shall  remain  valid  and shall be in full force and effect as to loans or
advances  made  pursuant  to and under the terms of this note subsequent to each
such  occurrence.

     Advances  hereunder shall be made by Payee upon the oral or written request
of  the undersigned officer of Maker or any other officer of Maker authorized to
make  such  a  request.

     Maker  promises  to  pay to the order of Payee at the place for payment and
according  to  the  terms  of  payment the principal amount plus interest at the
rates  stated  above.  All  unpaid  amounts  shall  be due by December 31, 2006.

     On  default  in  the  payment  of  this  note  or in the performance of any
obligation  in  any  instrument  securing  or collateral to it this note and all
obligations  in  all  instruments  securing  or  collateral  to  it shall become
immediately  due at the election of Payee.  Maker and each surety, endorser, and
guarantor  waive  all demands for payment, presentations for payment, notices of
intention  to  accelerate  maturity,  protests,  and  notices  of  protest.

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     If  this note or any instrument securing or collateral to it is given to an
attorney  for  collection,  or  if  suit  is brought for collection, or if it is
collected  through probate, bankruptcy, or other judicial proceeding, then Maker
shall  pay  Payee  all costs of collection, including reasonable attorney's fees
and  court  costs,  in  addition  to  other  amounts  due.

     Interest  on  the  debt evidenced by this note shall not exceed the maximum
amount  of  nonusurious  interest  that  may be contracted for, taken, reserved,
charged,  or  received  under law; any interest in excess of that maximum amount
shall  be  credited  on  the  principal  of  the debt or, if that has been paid,
refunded.  On  any  acceleration  or  required or permitted prepayment, any such
excess  shall be canceled automatically as of the acceleration or prepayment or,
if  already  paid, credited on the principal of the debt or, if the principal of
the  debt has been paid, refunded.  This provision overrides other provisions in
this  and  all  other  instruments  concerning  the  debt.

     The  terms  Maker and Payee and other nouns and pronouns include the plural
if  more  than  one.  The  terms  Maker  and Payee also include their respective
successors,  representatives,  and  assigns.


                                      MAKER
                                      INTERNATIONAL  TEST  SYSTEMS,  INC.




                                      BY: /s/ Carey G. Birhmingham
                                         ---------------------------------
                                         CAREY  G.  BIRMINGHAM
                                         PRESIDENT,  CEO AND SOLE DIRECTOR

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