oounter for litres of gasoline

I am locking for a counter of litres of gasoline, to be conecter in the pistol of the gas expending machine and before to inside of the gas deposit in the car. to be sure than the litres in the gas expending machine are the exacts. because here in Mexico the gas stations have a software to alterate the pumps. thanks,

Nicolas Reyes C. from Mexicali Baja California Mexico