3650mAh Extended Battery fits HP iPaq hx4700 hx4705 series High Quality, high capacity, light weight rechargeable DC 3.7V Li-Ion 3650mAh battery. Longer battery life than the original battery that comes with the PDA. Best replacement for the original HP iPaq hx4700 hx4705 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.