It will automatically emit ultrasonic waves that the dog can hear, the built-in pickup can detect the dog's barking(The ultrasonic anti-bark device can automatically detect bark within 50 feet.), and effectively training your dog to stop excessive and noisy barking. After the dog stops barking, the ultrasonic barking control device automatically stops emitting ultrasonic waves.  No noise pollution: The mini bark control uses ultrasonic technology that allows humans to hear a slight sound. When the sound starts, the dog will notice the sound and ultrasound does not impose substantial penalties on the dog. Other family members or neighbors will not be worried about being affected.  The dog bark control shell UV resistance, not easy to fade.It can be easily hung on trees,indoor, outdoor walls or fences to stop any dog barking . And the shell is IP45 waterproof grade, which can effectively resist external splash. Sensitivity adjustment: The barking control devices  has a choice of 4 sensitivities. Level 1 is the least sensitive and level 4 is the most sensitive. It can be set to the best suitable gear according to the use of the environment. Large frequency range: The anti barking device ultrasonic has 4 frequencies to choose. Each dog could choose the suitable frequency, and if the dog was not sensitive to this by using for a long time, please change the different frequency better. The 15/20 kHz frequency is most commonly used in dogs to stop barking.  With the increase of ultrasonic power, the scope of coverage is wider and the ultrasonic stimulation is strong. 100% safe for human and animals. Digital display, USB interface for charging. Specifications: Color: Black Material: Plastic Charging: USB Package Size: 12.5 * 9 * 5cm Package Weight: 200g Package List: 1 * Anti Barking Device 1 * USB Charging Cable 2 * Mounting Screws and Anchors 1 * User Manual