Flexzion Ultrasonic Dog Bark Control Outdoor Pet Anti Bark Deterrent Stop Barking Device Bird House Box Design Waterproof for Home Garden Hanging Battery Operated Uses ultrasonic sound to deter unwanted barking from either your or your neighbor's dogs Safe and effective for all size and breeds of dogs.This device with battery operated Detects barks up to 50 feet with the use of an internal microphone 4 Levels of operation including a test mode. 9V Battery operation - (battery not included) Durable and weatherproof for outdoor use, easy hanging or mounting on a tree, wall or fence