MiLi Power Spring 4 HI-C23 External Battery Case 1600 mAh Capacity for iPhone 4 (White/Silver) The worldwide highest capacity external battery for iPhone 4. Product Dimension: 124 x 65 x 18 mm. Technical Specifications: Input: DC 5V/500mA, Capacity: 1600mAh. Standby time: Up to 360 hours. Talk time: Up to 6 hours on 3G, Up to 13.3 hours on 2G. Internet Use: Up to 6 hours on 3G, Up to 10.6 hours on Wi-Fi. Audio play: Up to 36 hours. Video play: Up to 10.6 hours. Package Contents: MiLi Power Spring 4, Mini USB cable, User's Manual.