[ ]The ASNXBXW built-in pickup can detect the dog's barking, and the dog barking control device will automatically emit ultrasonic waves that the dog can hear, effectively training your dog to stop excessive and noisy barking. After the dog stops, the ultrasonic barking control device automatically stops emitting ultrasonic waves. [ ]The rechargeable anti barking device ultrasonic has 4 frequencies to choose from, Each dog could choose the suitable frequency (15KHZ-30KHZ), and if the dog was not sensitive to this by using it for a long time, please change the different frequency better. The dog device is suitable for dogs between 6 months and 8 years of age, except for dogs with hearing impairments or under 6 months and special large dogs. []The mini bark control uses ultrasonic technology that allows humans to hear a slight sound but is not affected by the sound. When the sound starts, the dog will notice the sound and other family members or neighbors will not be worried about being affected. Ultrasound does not impose substantial penalties on the dog. [ ]The barking control devices shell UV resistance, not easy to fade. It can be easily hung on trees, indoor, and outdoor walls, or fences to stop any dog barking (an Ultrasonic anti-bark device can automatically detect bark within 33 feet). And the shell is IP4 waterproof grade, and can effectively resist external splash. But if it rains, it's best to take it back, which helps protect the equipment and extends its life. [ ]The barking control device ultrasonic has a choice of 4 sensitivities. The environment can be set up with the best suitable gear, the induction distance can be selected, adjust the sensitivity to achieve. Level 1 is the least sensitive and level 4 is the most sensitive.