High Quality, high capacity, light weight rechargeable battery. Longer battery life than the original battery that comes with the Headset. No memory effect. Can be charged or discharged as needed without loss of capacity. Overcharge protection, with built-in battery life microchip. CE Certified. Capacity: 60mAh Physical size: Same size as Original OEM Battery. Compatible Models: Sennheiser Set 500, IS 380, SET- 2500