So pleased to find this company and product, it has helped my deaf dog immensely that she is not being caught unawares anywhere near as often by people. My other dog is also nervous of people now as they seem to launch themselves to talk to him and he has become nervous now, this gives the warning not to do this and him the chance to relax more when out once again. As someone who does not encourage anyone to talk to a dog before talking to the owner, I am so pleased I have finally found away to highlight this in a friendly way to people. so very pleased with this product in conjunction with their vests. Brilliant couldn't recommend them enough and the prompt service also.