Features: It will automatically emit ultrasonic sounds that the dog can hear, the built-in sensor can detect the dog's barking (the ultrasonic anti-bark device can automatically detect the barking within 50 feet) and effectively train your dog to stop the barking.excessive and loud barking.Once the dog stops barking, the ultrasonic bark control unit will automatically stop emitting ultrasound. No Noise Pollution: The mini bark control uses ultrasonic technology to allow humans to hear light sounds.When the sound begins, the dog notices the sound and the ultrasound does not cause a substantial penalty to the dog.Other family members or neighbors will not be afraid of being affected.The dog bark control case is UV resistant and not easy to fade.It can easily be hung on a tree, interior wall, exterior wall or fence to stop any dog from barking. The case is IP45 waterproof and effectively resists external splashes. Sensitivity adjustment: The bark control device has 4 sensitivities to choose from.Level 1 is the least sensitive and level 4 is the most sensitive.Can be adapted to the most appropriate equipment depending on the use of the environment. Wide frequency range: the ultrasonic anti-bark device has 4 frequencies to choose from.Each dog can choose the right frequency and if the dog is unresponsive for a long time, it is better to change the frequency.The 15/20 kHz frequency is most often used to stop barking in dogs.With the increase of ultrasound power, the coverage is wider and the ultrasound stimulation is stronger.