Dog Bark Control and Dog Training - Our ultrasonic barking control devices provide a safe and effective solution for dog training and bark control. The anti bark device can effectively train your dogs to stop unwanted behaviors such as barking, digging, eating unsafe food, fighting, etc.Suitable for All Size Dogs - The average human hearing frequency range is 20HZ~20KHZ, and the dog can hear a wider range from 15HZ to 120KHZ. MODUS ultrasonic bark control emits ultrasonic sound at 25KHZ, so the sound doesnt affect humans, but can grab dogs attention.ultrasonic dog barking deterrent devices just fit nicely in your hand and comes with an adjustable anti-static wrist strap.As we use ultrasonic technology, it works effectively on all sizes of dogs.The ultrasonic anti barking device doesn't effective in dogs with hearing problems and we dont recommend using this product on dogs under six months or above 8 years old. Training is required to achieve highly effective and long-lasting use.