Gentle spring action makes your dog fence safer and more comfortable too! Great for dogs with any type of coat! Fits most dog fence collars that accept a screw-in contact post. Can be used with all Perimeter Technologies Systems, PetSafe PIF-300 and PetSafe PIF-275-19. Can be used with all Perimeter Technologies Systems PetSafe PIF-300 and PetSafe PIF-275-19 Gentle spring action allows the contacts to adjust to your dog Fits most dog fence collars that accept a screw-in contact post.