BXT&reg; iPhone 4 / 4s External Rechargeable Spare Backup Extended Battery Charger Case Cover for Apple iPhone 4 / 4s (2000mah, Pink) Extended power pack for your iPhone ,available charging when walking ,having class,on work,on the subway,in car.Anywhere at anytime! Easy using,slide your iphone 4/4S to the bottom,place the roof cover back and it's all right now.Turn it ON when charging. Be convenient,you can just keep it in hand .Easy carrying with and offer extra full protect to your iPhone Extend standby time up to 215 hrs for iPhone 4/4s;talk time up to 8.5hrs;Audio play 25hrs Capacity:2000mAh;Size:13*6.5*2 cm; Weight:75g;Mate