The iPhone Air MagSafe Battery is Apple's own battery accessory made only for iPhone Air. It is designed to slip into a pocket and sit comfortably in the hand. It adds up to 65 percent additional charge to iPhone Air, and Apple says that gives iPhone Air longer battery life than any other iPhone. For field staff, travellers and anyone who works away from a desk, it is a compact way to keep iPhone Air running through long days. The battery manages charging on its own. Attach it to a fully charged iPhone Air for all-day use, and the combined system chooses the best times to recharge to maximize battery life. When you need a quick boost, snap it on for up to 12W of fast wireless charging. At a desk or in a vehicle with a wall outlet, attach the MagSafe Battery to iPhone Air and connect it to a 20W or higher power adapter at the same time for even faster charging of the phone. The battery can also charge smaller accessories through USB-C, so one pack can top up other gear when you are away from an outlet. Apple part number MGPG4AM/A. The box contains the iPhone Air MagSafe Battery. Apple lists compatibility with iPhone Air only.