scoobiesteve103

Afternoon all, a while back my newage wrx clocks stopped working so I bought a set of sti clocks with the shift light but the new clocks was a fee k less then the mileage on my car.ive kept tabs on the mileage ect and now have a set of defi clocks to fit so would like to change the mileage to the correct miles of the car. Is there any tool I can buy to do this myself? Don't need nothing fancy as it's only my own car.
Tia Steve