TrackR bravo Item Trackers: Easily locate your cell phone, wallet and other lost items with these trackers and the TrackR app (download required). Bluetooth 4.0 connects to your compatible mobile device from up to 80' away, and you can also find out-of-range items when other users walk by.
I am currently on my third set of devices and each time at least one of them quits working within a couple weeks. I was very excited about this product, but I am now disappointed. I will be returning them and finding another brand or just wait until they are better quality.