【Pet-Friendly Anti-Bark Device】This ultrasonic bark control device works by sending out a stable frequency sound that only dogs can hear, which helps dogs avoid annoying voice that causes barking. The anti-bark device is harmless to dogs' hearing, perfect for creating a quiet room for dog lovers, stopping unwanted behaviors such as barking, digging, fighting, etc. 【Effective on All Size Dogs】The ultrasonic dog bark deterrent with 3 levels adjustable sensitivity and frequency (15-30KHz for big vicious dogs; 20KHz for docile dogs; 30Khz for small dogs) easily deal with different barking dogs. Adjusting frequency for each week can keep the training effect. The wide control range of 33ft (10m) is suitable for stopping the neighbor's dog from barking at you and your family. 【Easy to Use】This rechargeable dog bark control device with indicator light can be used without any effort. The light will flash blue when working; Red light when the sonic anti bark device is triggered by barking; the