1.PROFESSIONAL DOG TRAINING WHISTLE:The dog training whistle is professional engineered, can produce frequencies in a range of 5.4KHz and 12.8KHz when whistle it. The whistle is audible to the human ear, but it's not loud. Dogs are able to hear these sounds because they are very sensitive to high frequencies 2.SAFETY:This dog training silent whistle will help you train your dog and eliminate or stop dog barking along with obeying basic commands. Whether your puppy is naughty or not, this is a safe way to train it, without harming it 3.ADJUSTABLE FREQUENCY: The frequency of ultrasonic whistles is adjustable. You can train your dog to listen to different commands in this way. Please note that your dog need to be trained for multiple times to understand your instructions 4.WHISTLE LANYARD: You will receive FREE matching whistle strap with your whistle.It is small and light weight,This way you can hang your dog whistle around your neck and have it ready to hand at all times.Conveniently To Carry 5.APPLICATION: Train your dog with the ultrasonic whistle and clicker so that you don't need to shout out loudly, you will have a happy and trusting communication tool with your petAPPLICATION: Train your dog with the ultrasonic whistle and clicker so that you don't need to shout out loudly, you will have a happy and trusting communication tool with your pet. WHISTLE LANYARD: You will receive FREE matching whistle strap with your whistle.It is small and light weight,This way you can hang your dog whistle around your neck and have it ready to hand at all times.Conveniently To Carry. ADJUSTABLE FREQUENCY: The frequency of ultrasonic whistles is adjustable. You can train your dog to listen to different commands in this way. Please note that your dog need to be trained for multiple times to understand your instructions. SAFETY:This dog training silent whistle will help you train your dog and eliminate or stop dog barking along with obeying basic commands. Whether your puppy is naughty or not, this is a safe way to train it, without harming it. PROFESSIONAL DOG TRAINING WHISTLE:The dog training whistle is professional engineered, can produce frequencies in a range of 5.4KHz and 12.8KHz when whistle it. The whistle is audible to the human ear, but it's not loud. Dogs are able to hear these sounds because they are very sensitive to high frequencies.