Baixt iphone 4 / 4s External Rechargeable Spare Backup Extended 2200 mAh Battery Charger Pack Case Cover for Apple iphone 4s Black Extended power pack for your iPhone ,available cha Easy using,slide your iphone 4/4S to the bottom,pl Be convenient,you can just keep it in hand .Easy c Extend standby time up to 215 hrs for iPhone 4/4s; Capacity:2200mAh;Size:13*6.5*2 cm; Weight:75g;Mate