Humutan Anti Barking Device,Bark Control Device with Ultrasonic to Stop Dog Bark,Dog Barking Deterrents with Adjustable Level SonicAnti Barking & Dog Training DeviceKaiercat anti dog barking device intelligently captures dog bark in the area covered by the system, and automatically emits ultrasound to silence dog for solving excessive and noisy dog barking Safe and HarmlessBark stopper adopt new ultrasonic technology, it's a kind of safe sound wave with a frequency more than 20KHz, harmless to dogs and completely inaudible to human ears. 4 Levels Operation The Anti bark control