1050mAh Extended Battery fits HTC S620, Dopod C720W, O2 XDA Cosmo, T-Mobile Dash series High Quality, high capacity, light weight rechargeable DC 3.7V Li-Ion 1050mAh battery. Longer battery life than the original battery that comes with the PDA. Best replacement for the original HTC S620, Dopod C720W, O2 XDA Cosmo, T-Mobile Dash series battery pack. No memory effect. Can be charged or discharged as needed without loss of capacity. Overcharge protection, with built-in battery life microchip.