Works well. Put the bear part on your childs clothing. I secured it with a small plastic Cable tie (available in hardware stores). This meant the bear couldn't be removed easily. Attach the key ring fob to your belt. When your child disappears in a crowd, just press the button on the key ring fob. The bear then emits a loud beeping sequence which lasts about 10 seconds. It is loud enough to locate your child in a busy shopping centre. You can keep pressing the button if necessary to give a second or third series of beeps. You can also tell your child what you want them to do when the bear beeps so that you can find them quicker. We tested ours over a week long period and had occasion to press the button about 10 times. It worked every time. The range is about 20 or 25 metres, which might not seem like very far, but it is actually plenty, as a kid will only usually be only be gone 5 seconds before you realise they have bolted. In a crowded place it is very likely that they will still be in range when you hit the button.