PetSafe Multi-Room Indoor Bark Control System FOR DOGS OF ANY SIZE  uses high-frequency sound that works for dogs of any size within hearing range VERSATILE  water resistant units can be adhered to doors or window frames or set on a shelf or table ADD ADDITIONAL UNITS FOR MULTI-ROOM COVERAGE  each unit detects barks up to 25 feet away BEST FOR SINGLE DOG HOMES  unit is freestanding and can correct all dogs within hearing range BATTERIES INCLUDED  uses 2 3-Volt CR-2032 batteries (included) NO BARK GUARANTEE - Some dogs may not be responsive to ultrasonic correction. If this product is not meeting your needs, please contact PetSafe Brand Call, chat or email with our expert PetSafe US-based customer care specialists six days a week; They are waiting to assist you and your pet with your product needs at 1-800-732-2677 or by email at ccc3@petsafe.net Manufacturers warranty is only valid when purchased from an authorized retailer