Dog Ultrasonic Bark Control Device Bark Control Outdoor Bark Control Dog Bark Control Sonic Bark Control Quiet Stop Barking. Features: The ultrasonic anti-bark devices automatically detect barking as far away as 15m / 50ft. The bark control device automatically emits high-pitched sounds that only dogs can hear. Once the dog stops barking, the ultrasonic bark control will automatically stop emitting ultrasonic sounds. Ultrasonic frequencies are harmless to pets and completely inaudible to the human ear, so you can use this device safely. < ; p> Can be hung on a tree, indoor, outdoor wall or fence post to deter dogs from barking (within reach). When the deluxe ultrasonic outdoor alarm clock detects excessive barking, the microphone responds to the barking and echoes the activation. 9V batteries are required (batteries are not included). The outdoor ultrasonic barking device has a power indicator. When you leave, it can be turned off to save battery. Designed for outdoor use, outdoor