High Quality, high capacity rechargeable battery. No memory effect. Can be charged or discharged as needed without loss of capacity. Overcharge protection, with built-in battery life microchip. Volts: 3.7V Battery Type: Li-ion Capacity: 2200mAh/8.14Wh Dimension: 68.00 x 18.30 x 18.30mm Compatible Part nos: NTA2335 Compatible Models: Logitech Pure-Fi Anywhere Speaker 2nd MM50