Usage Tips: Pet Dog Ultrasonic Bark Control Device Bark Control Outdoor Anti Barking Dog Bark Control Sonic Bark Deterrents Silencer Stop Barking Features: Ultrasonic anti-barking devices automatically detect barking from as far away as 15m / 50 feet. The barking control device automatically emits high-pitched sounds that only dogs can hear. Once the dog stops barking, the ultrasonic bark control automatically stops emitting ultrasonic sounds Ultrasonic frequencies are harmless to pets and completely inaudible to the human ear, so you can use this device safely Can be hung on a tree, indoor, outdoor wall or fence post to stop any dogs barking(within range). When the luxury outdoor ultrasonic barking alarm clock detects excessive barking, the microphone will respond to barking and activation parts It needs 9 V batteries - (batteries are not included). The outdoor ultrasonic barking device has a power indicator. When you leave, it can be set to "Off" to protect the battery.Designed for outdoor use, outdoor ultrasonic barking device.