Clix Silent Whistle

This lightweight, compact whistle is ideal for dog training, indoors or out.
Ultrasonic whistles are particularly suited for training noise-sensitive breeds such as border collies.
Although termed as a 'silent' whistle, the whistle has to be slightly audible to the human ear, in order for you to be able to effectively control your dog - as otherwise you would not be able to gauge the effect that it is having.