[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 the dog is hearing impaired or aggressive, the device may not work as expected. [Stop Dog Barking Indoor and Outdoor]: When tested, the anti barking device works best within 32 feet and completely frees up your hands compared to traditional dog trainers. You can easily train your dog's behavior by turning the knob. Perfect for discouraging neighbors and homeless dogs from barking outdoors. [USB Rechargeable Dog Barking Control Devices]: charging anti barking device, with indicator light, easy to use. A 5-hour charge lasts 30 days, saving you endless hassle and battery investment. No battery required, out of the box. (It is recommended to fully charge before use, the effect will be better)