I/O Magic Universal Rechargeable USB Battery Power Pack for Cellphones, Smartphones, MP3 Players, and More (3500mAh) Universal Portable Charger - Perfect for charging mobile devices Compatible with the iPhone, iPod, Smartphones, Cellphones, MP3 Players, Cameras, Bluetooth Headsets, Portable Gaming Devices, GPS Units, and Hundreds More 3500mAh Lithium Polymer Battery extends battery life up to 45 hours Standard USB Connection is compatible with hundreds of devices Intelligent Protection - Prevents Overcharging, Undercurrent, and Short Circuits