Adjustable Whistle: Different dogs respond to different frequencies. Our dog training whistle has a nut and screw that will adjust the frequency when turned. Note your dog's reaction at each setting until your dog exhibits the loudest reaction. Effective Training: Your pet can hear your dog's whistle from a long distance, even if he can't see you. Train your dog with different commands and ask him to follow your instructions like sit, paw, lie down, etc. Stop dog barking: When your dog or neighbor keeps barking, gently blow the dog whistle and the ultrasonic frequency emitted by the whistle can easily attract the dog's attention and stop its barking. With lanyard: Each dog whistle is equipped with a long lanyard, which allows you to carry the whistle anywhere easily. The plastic sleeve can help you keep the dog whistle better when you don't use it. For all dogs: This dog whistle cannot be heard by humans. This silent product is suitable for all dog breeds. With this useful whistle,