High Quality Whistle: Our dog whistle is made of high quality stainless steel, 100% safe, strong and durable. The ultrasonic dog whistle will not affect your dog's hearing. dog training. Easy to Use: Our ultrasonic dog whistle trains dogs to perform different actions by emitting sounds of different frequencies. It should be noted that every time you whistle, you need to pay attention to the reaction of the dog, so that the dog can be gradually trained to become familiar with the sound and take appropriate action. Adjustable Frequency: The precise cut of the dog whistle allows for a finer frequency range that is barely audible for humans but sufficient for dogs. By adjusting the adjusting nut and lever to get different sound frequencies, you can watch your dog respond to each sound for better training. Train Multiple Movements: With our dog whistle, you can train your dog to perform proper movements without yelling. For example: stop barking, sit down, shake hands, remember, etc. PERFECT SIZE: With this small, high-quality whistle, you can always find the best frequency, especially for your dog. Whether training puppies or older dogs, the whistle works in the high range frequencies, so it's not particularly loud to humans, but very audible to dogs.