When the PetSafe® Indoor Bark Control is within range of a barking dog, an internal microphone picks up the sound. The unit automatically emits an ultrasonic tone that can be heard by dogs but is silent to most humans. Startled by the high-pitched tone, the dog should stop barking. In time it will associate its bark with this unpleasant noise. When the dog stops barking, the ultrasonic tone also stops. It is effective up to 8 metres.

Features: Automatically deters excessive barking, No collar needed, Two units included for multi-room coverage, Freestanding or can attach to doors, windows, tables, etc., For dogs of any size, Range up to 8 metres, Ultrasonic sound only your dog can hear, Microphone detects bark, Water resistant, For indoor use only, Good/low battery indicator, suited for single dog households. System Includes: 2 Indoor Bark Control Units, 2 Self-Adhesive Hook and Loop Mounting Strips, 4 x 3-Volt Lithium CR2032 Batteries, Operating Guide.