A small device that is attached to items such as a phone, tablet, keyring or wallet for tracking purposes. A mobile app communicates with the tracker via Bluetooth, and the tracker can be signaled to sound a beep when the item cannot be found. The app also records the location of the tracker the last time it was in range.
Even When Out of Range
When the tracker is out of Bluetooth range, the assistance of all other users with that same tracker app is enlisted behind the scenes. All running apps pick up the signals from the trackers of all the users of the same product in the vicinity. The signals sent to the vendor's cloud are used to pinpoint their geographic locations. See vehicle tracking
The Tile (left) and TrackR Bravo (right) are examples of Bluetooth trackers that are small enough to place almost anywhere.