Our replacement batteries are guaranteed to work with your PetSafe® brand collar. The battery cell is identical in type to the one used in the PetSafe® RFA-188 battery. Our battery casings are engineered to perfectly fit. This 3 Volt Batteries are used in all Petsafe® receivers that require 3-volt lithium battery module. Plenty of power for the best reliability. Coin slot for quick and easy installation. Built in gasket creates a waterproof seal.