HTC Evo 4G 3500mah Extended Battery + Cover (Red) + Standard Wall Charger + All in One Card Reader/writer + Silicone Wrist Band Extends your battery life almost up to 2 times! Actual battery life depends on software configurations and network settings Capaticy: 3500mAh (twice the capacity of OEM) Cell: Lithium Ion, Voltage: 3.7V Colorful silicone wrist band