As is well known， Apple iPhone is the world&acute;s most popular smart phone. The only flaw is that the battery is not replaceable. It is painful for such people: business people and mobile phone game players. They need the mobile phone with high performance and long battery time. Today we provide with you a external backup battery case， specially designed for iPhone. It can not only serve as a good protective case， but also as a portable external backup battery. It made of non-slippery material， good touching. Besides， all function buttons and ports are accessible without removing the cover， simple and convenient. The personalized battery case is designed for you， come to have a try!                                    Features            Compatible with Apple iPhone 3Gs 3G<br>Leather Case Cover. Built-in rechargable 1500mAH Li-Ion battery<br>Protects against impacts and shock<br>High Power Capacity and Rechargeable<br>Doubles your battery life<br>Very convenient and easy to use<br>Slim and secure fit to your iPhone<br>                                                            Specifications                    Cell type          Li-Polymer battery        <br>      Capacity          1500mAh        <br>      Output          DC 5V， 500 mA        <br>      Talk time          Up to 5 hours on 3G        <br>      Internet Use          Up to 4.5 hours on 3G<br>Up to 5 hours on Wi-Fi        <br>      Standby Time          Up to 240 hours        <br>      Audio Play          Up to 17 hours        <br>      Video Play          Up to 5 hours        <br>      Read/write emails          5 hours        <br>      Gameplay          3 hours        <br>      Dimension          135 x 65 x 21 mm / 5.31" x 2.56" x 0.83" (L x W x T)        <br>                                                              Package Includes            1 x 1500mAh Leather Case with Backup Battery for iPhone 3G/3GS Black & Red<br>1 x USB Cable<br>                                                            Extra Info            Compatibility: iPhone 3G / 3GS<br>