Sunbeam Sonic Egg Ultrasonic Bark Control Device preowned tested and works The Sunbeam Sonic egg bark control device emits a pet-safe, ultrasonic sound at 3 levels that only dogs can hear— a method used by professional dog trainers deter your dogs or nieghbor dogs from annoying barking Battery-operated bark control device works with any breed of dog and has a 50-foot range; weatherproof design can stand alone, mount to a wall, or hang from a fence or tree LED indicator light shows when in use; light changes to red when battery needs to be changed Takes one 9V battery (not included); 1-year warranty Not intended to protect against aggressive dogs; should only be used to deter barking; keep out of reach of children; this ultrasonic noise device should not be used less than 12 inches from a human ear