The bluetooth tracker could connect with phone's bluetooth, function of bidirectional search, which can connect the GPS tracer anti-lost. Both tracker and phone ring if they are far apart over 25 m. You can find lost item by checking the last location when it's disconnected. For small accessories (such as key rings, bags, etc.), it can also be used as a remote control to take a picture, very convenient. It's for children, the elderly in some special environments (such as shopping, travel, etc.). And, it's also for animals, so that they can enjoy the playing time, no need to worry it's lost.