Amazon.com : PetSafe Compatible RFA-188 Replacement Batteries (5-Pack) : PET STANDARD : Pet Supplies
RFA-188 - Dog Collar Bark Control Battery suitable for all PetSafe Nano Collars, PetSafe Deluxe Cat Containment Collar, PetSafe Little Dog Deluxe Anti Bark Collar, PetSafe Big Dog Deluxe Anti Bark Collar
PetSafe RFA-188 Replacement Dog Collar Battery at Tractor Supply Co.