The principle of the whistle is simple, follow the process of training your dog to respond to the sound of the whistle and interpret it into instructions you have previously taught, this can be anything from simply returning to your side from a distance, to advanced tricks such as sit, beg and roll over. (If you are feeling adventurous, try combinations such as one long blow for return, and multiple shorter ones for different tricks / commands).
The clicker element acts as a reward mechanism for responding to tasks successfully. The guide explains how to use food / treats to associate good behavior with a click. This reward system can then be used in conjunction with the whistle commands, voice commands, or just as a way of calming your dog, as it remembers that a click could mean food or other rewards.
This whistle / clicker doesn't look out of place on any keyring, thanks to its modern, lightweight and rounded design. It is durable, being made of hard plastic, available in 3 colours and the clicker element is stainless steel, so won't rust.