is is the most universal of all whistles.
Plastic Shepherds Whistle
This is the most universal of all whistles. The advantage of using this whistle is you can vary the pitch to make any sound you feel comfortable with. Once you have learned how to make a variety of sounds, you can teach your dog what you want him to do on a sound of your choosing. The dog will respond a lot better to the sound of a whistle than a voice command because he can hear the whistle sound at a long distance as well as up close. Professional dog trainers around the world use this whistle to teach their dogs many different activities. For example you can teach your dog to down, here, right, left