This extra Receiver Collar can be used to add another dog to any PetSafe® In-Ground Fence™ system or as a replacement collar to the Stubborn Dog In-Ground Fence™ system. This collar is not a complete system and needs to be used with a compatible transmitter. Features Highest intensity level available Over Stimulation Protection: Stimulation stops after 30 seconds Uses 1 x 9 Volt battery (not included) Battery usually lasts 1-3 months Collar Size: Fits neck sizes 15 - 71 cm Covers up to 13 ares (1/3 acre/0.13 hectares) with included boundary wire Compatible with PetSafe® In-Ground Fence™ systems (excluding Classic In-Ground Fence) Waterproof Safe, Effective, Trusted - Our static collars are part of our ongoing mission to provide the best tools, education and support for pet parents seeking safe, successful, expert-recommended options to meet each dog’s unique training needs