While the tile key locator is not actually a GPS device because it is constantly looking for a nearby bluetooth device with the tile ap and that device will by default have GPS it is able to find something lost away from your phone or home.
When you install the tile ap on your device – usually your phone – it sets up a link into the cloud based service provided by Tile.
When the Tile is lost, and any device with the Tile ap comes within bluetooth range that device in the background, forwards to the cloud the current GPS coordinates of that device and therefore the Tile.
When you want to find the Tile you click the find on the ap, your device sends the request to the cloud, the cloud responds with the current location and your ap displays the Tiles last know location.
The tile is sold as a key finder but it will work on about anything, a purse, a dog, a car, just about anything. With a little imagination it could find a lost child, or missing spouse, it is your imagination. Now if you were to use it to find your wayward spouse you probably should not activate the find my phone feature to your own phone – it will ring your phone if the button on the Tile is pressed twice.