Stop losing your keys or leaving your wallet behind with the Nokia WS-10 Treasure Tag Mini Proximity Sensor with Bluetooth 4.0. These sensors are the perfect way to keep those important items close. Simply attach a sensor to your belonging, and you'll be able to quickly see where your item is using the app. Plus, if you walk out of reach of the sensor, you'll instantly get a notification on your phone letting you know you've left your belonging behind. The tags work with iOS, Android, and Nokia Lumia devices, and are simple and easy to attach! Attach using use the included straps, stick them on a key ring, or come up with your own way to attach them to important devices. Now, you'll never leave important items behind again.