These PetSafe Compatible RFA-188 Replacement Batteries are an excellent choice for people who own a compatible PetSafe brand collar. The battery cell is identical in type to the one used in the PetSafe RFA-188 battery. The battery casings used in this electronic accessory engineered to fit. The 3 volt batteries can be used in all Petsafe receivers that require 3 volt lithium battery module. These Petsafe collar batteries offer power, reliability and a coin slot for quick and easy installation. The built-in gasket creates a waterproof seal.PetSafe Compatible RFA-188 Replacement Batteries (Pack of 5):