The 2 pack MFI Air Trackers is perfect for keeping up with your personal belongings. They're small, lightweight and can be used on your backpack, purse, keys, luggage, bike, in your wallet and so much more. They can even be used on pet collars! It's easy to use; the MFI Air Tracker works with Apple's 'Find My' app. Simply pair it with your device (which takes about 30 seconds), open the app and click 'Play Sound' to locate your item! Note: Android devices are not supported.