LOPURS Bp-6m Standerd Battery for Nokia N73, N93, Back up Battery Battery Specs. Capacity: 1100mAh. Battery type: Lithium Ion, Voltage: 3.7V Li-ion Good quality and durable to use It is recommended to fully drain and fully charge the battery especially during the first 3 charging and discharging cycles, doing so may greatly improve the overall life of the battery