Portable external backup battery charger for Galaxy S2 i9100 using the cell phone while charging. Light-weight super-slim design to carry with your device and provides protection to your device as well in style. Conveniently recharged via any USB ports high-capacity 2800mAh rechargeable lithium-ion battery can meet almost digital products demands. Quantity 1 Piece Color Black Material Plastic Compatible Models Samsung Galaxy S2 i9100 Battery Type Li-ion polymer Capacity 2800 mAh Input Voltage 5 V Output Voltage 5 V Features Stylish and practical great for travel use Packing List 1 x External battery back case