2200mAh Li-Ion Replacement Extended Battery for Google G1, T-Mobile G1, HTC Dream, HTC Dream 100 series High Quality, high capacity, light weight rechargeable DC 3.7V Li-Ion 2200mAh battery. Latest Lithium Ion battery technology gives the best performance possible compared to other battery technologies such as Nickel Metal Hydride (Ni-MH). No memory effect. Can be charged or discharged as needed without loss of capacity Overcharge protection, with built-in battery life microchip CE Certified