"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 NO BARK GUARANTEE: Some dogs may not be responsive to ultrasonic correction. If this product is not meeting your needs, please contact our Customer Care experts CUSTOMER CARE: Let our pet product experts help; we’re available Monday through Saturday to answer your questions at PetSafe QUALITY GUARANTEED: PetSafe brand has been a trusted global leader in pet behavior, containment and lifestyle innovations for nearly 30 years; we help pets and their people live happy together"