PetSafe Stubborn Dog In-Ground Fence for Dogs, Waterproof, with Tone, Vibration and Static Correction FOR STUBBORN OR HARD TO TRAIN DOGS - 4 adjustable levels of static correction; highest intensity available TONE AND VIBRATION WARNING - ideal for training hearing-impaired dogs. Tone-only mode alerts your pet with a beep SAFE AND CUSTOMIZABLE - gives your pets room to play with up to 1/3 of an acre coverage, expandable up to 25 acres with the purchase of additional wires and flags (sold separately) WATERPROOF RECEIVER COLLAR - for all of your dog's outdoor activities. Transmitter with power adapter. Battery : 9-volt alkaline battery ADJUSTABLE COLLAR - fits pets 8 lb. or more with neck sizes 6 to 28 inches. Works with 14-20 gauge copper insulated wire ADD UNLIMTED PETS - with the purchase of compatible PetSafe In-Ground receiver collars (Excludes YardMax and UltraSmart) Transmitter with power adapter