Dog Bark Deterrent Devices, Anti Barking Device for Dogs Barking Silencer Dog Whistle Up to 50ft Stops Bad Behavior Dog Training Tool, 3 Modes & LED Light Ultrasonic Dog Trainer Indoor OutdoorSafe & Humane The barking dog deterrent uses ultrasonic sound, which is inaudible to humans but easily detectable by dogs. This sound attracts the dog's attention without causing any physical pain or distress like a shock collar, ensuring a positive learning environment. To further ensure safety, the dog barking silencer includes a 10 second auto off feature that prevents prolonged exposure to ultrasonic sound, protecting the dog's hearing. Dog Bark