This is a 1000mAh USB Rechargeable External Backup Battery for iPhone iPod. It is excellent for long trips and as an emergency backup when your iPhone/iPod's battery drains on the go. It's a rechargeable battery. Just snap it on gently then it begins to charge instantly. In the market, some batteries are not certified, or just use gray market parts, or may even damage your iPhone. But this external battery for iPhone is one that is a high-quality aluminum case, which is light but extremely anti-scratch. This is a great accessory for your iPhone/iPod. The polymerized lithium-ion external backup battery can be recharged over and over again. It is really suitable for long time using. Just place your order today!