The iOS KeyFinder app works with KeyFinder devices, which are advanced hi-tech object finders used to locate keys and other objects from your iPhone. The devices use Bluetooth Low Energy (BLE) and operate on a CR2032 coin cell battery.
You can keep a track of up to 4 KeyFinder devices through the app. The signal strength indicator gives you a rough idea of how far away the object is from your iPhone. The app also shows the battery levels, which are refreshed every time you use the app. Because the devices use Bluetooth Low Energy, the battery consumption is low.