So you want to be able to control your dog in any situation and get him or her to return with just one whistle? It can be done - with the double tone whistle JULA and, of course, with a bit of targeted training. This dog whistle lets you produce two different tones in different frequencies. This allows you to summon your dog in an emergency when he or she can no longer hear your call. The double tone whistle is made of plastic which makes it both pleasantly light and weatherproof. It can be easily attached to your clothes with a clip or hung around your neck - whichever you find most comfortable.