Bluetooth trackers are small devices that help you locate lost items, such as keys, wallets, or bags. They connect to your smartphone via Bluetooth, allowing you to track the item's location using a dedicated app. When you misplace an item, the app can show you its last known location on a map. These trackers often emit a sound to help you find them when they are nearby. Some models also feature a community network, where other users can help locate your lost item if it is out of your Bluetooth range. Popular brands include Tile and Apple AirTag.