Ultrasonic Bark Control Stop Device for Dogs - Pet Anti-barking Repeller Training Tool Ultrasonic Pet Anti-Barking Device Dog Bark Control Stop Repeller Silencer Training ToolFeature:Pet friendly anti-barking device: this ultrasonic barking control device works by sending a stable frequency sound that only dogs can hear, preventing dogs from barking and calming dogs. No irritating smell, no electric shock, anti-barking for dogs that only work when dogs bark. Bark repellent device is harmless to the hearing of people and dogs, perfect to create a quiet department for dog lovers and stop unwanted behaviour.Effective for dogs of all sizes: the ultrasonic dog barking repellent with 3 adjustable sensitivity and frequency levels (15-30 kHz for large, naughty dogs) 20 kHz for educational dogs 30 kHz for small dogs) prevent dogs of different sizes from barking easily. Adjusting the