[Upgraded Dog Training and Behavior Aid Tool]: The anti-barking device uses the latest ultrasonic technology to automatically emit high pitched sounds that only dogs can hear. Automatically senses the dog's sound, and once the dog stops barking, the ultrasonic barking controller automatically stops emitting ultrasonic waves. [Barking Deterrents for All Sizes and Breeds]: Anti barking devices are available in 4 sensitivities. You can set the most appropriate gear for your environment, select the sensing distance, and adjust the sensitivity to achieve this. Level 1 is the least sensitive and level 4 is the most sensitive. [Safe for Dogs and Humans]: The dog barking control device has no electric shock, no irritating odor, no buzzer, safe for pets, harmless to people, anti-barking device will automatically emit ultrasonic waves to stop the dog barking, very suitable for going out and letting the dog go. Keep the dog quiet to create a peaceful environment for your family and neighbors. If