Tile uses Bluetooth Low Energy 4.0 (BLE) technology to help you locate your items. While Bluetooth technology is a wireless technology, there are significant differences between Bluetooth, Wi-Fi, and GPS technology.
Note: Depending on your environment, the Bluetooth range might vary.
Learn more about Bluetooth at http://www.bluetooth.com/
If any other Tile user's phone/tablet is within Bluetooth range, you will receive an update with the location of your Tile. When this happens, you will see a pin on the map view for your Tile. This essentially makes the range limitless once there are enough Tile users in your area.
To learn about the range to find your phone please click here.