Safety is a priority for you and your pet. And you shouldn't have to sacrifice it because the strap has worn out. By taking your existing Petsafe collar system and changing the strapping to a Country Brook Design replacement collar, you can rest assured that you can still have all the benefits of your dog's fence while knowing our durable collar will keep up with your dog.One size fits most, so you won't have to worry about measuring. The full extent of this 1 Inch wide collar goes out to 30 Inches. Does your dog have a smaller neck? No problem! By sizing the collar down, you can easily cut away the excess material and burn the end to leave you with a perfectly fitted collar. Make sure to check the compatibility of your Petsafe system below. This design can be used with Petsafe models: IF-100, RFA-48, RFA-41, PIF-275, PIF-275-19 , PIF-300, PUL-250, PUL-275, PIG00-13737, PRF-275-17-19,PRF-3004W, PRF-304W, PIG00-14673, PIG00-13661, PIG00-14582, PIG00-10777, MIG00-10939, MIG00-10938, ZIG00-14658, and ZIG00-14654