I believe it really casts a damp over you when your mobile phone has run out of power. It means no business， communication and entertainment. So we are glad to recommend a perfect solution to all of you， i.e. our 2100mAh Clip-on External Battery Power Case Mobile Power Pack with Mini Back Support Stand for iPhone 4/4S. The power case is designed to offer all-around protection as well as durable power supply for your iPhone 4/4S. And with the back stand， you can enjoy wonderful movies， videos or other games in a more conveniently way. Expect your wise purchase!                                    Features             Portable and easy to carry， convenient and rapid charge<br> Thin and compact clip-on design<br> Electricity-saving function， long cycle life<br> Powerful with long operation time<br> Exquisite design， made of high quality material<br> Designed to fit your iPhone 4/4S perfectly<br> Stay connected with families and friends by getting extra battery power<br> With comparable standby and talk time<br> High battery capacity (2100mAh)<br> Also work as a reliable ABS protective case for your iPhone 4/4S<br> With mini back stand for supporting your device<br>                                                            Specifications             Charging Time     About 4 hours    <br> Capacity     2100mAh(Li-ion)    <br> Input     DC 5V/ 1000mA Max    <br> Output     DC 5V/ 500mA Max    <br> Material     ABS Plastic    <br> Weight     134 g / 4.73 oz    <br> Dimensions     (12.5 x 6.2 x 1.5)cm / (4.92 x 2.44 x 0.59)" (L x W x H)    <br> Color     Black    <br> Compatible with     iPhone 4/4S     <br>                                                             Package Includes            1 x Mobile Power Pack with Mini Stand for iPhone 4/4S