ANTI-BARKING CONTROLLER Easily hang on a tree or mount on a fence or wall to keep your dog or your neighbors dog from barking. 100% HARMLESS The ultrasonic frequency is safe & harmless to barking dogs and inaudible to humans. Can use it inside your home. WORKS FOR NEIGHBORS DOGS Place within range for the neighbors dogs to activate. EFFECTIVE RANGE 50 FT With 3 range levels settings and a test mode. Two color LED indicator show good or low battery. ACTIVATED BY BARKING It will detect barking dogs and automatically activate an ultrasonic sound to deter unwanted barking.