MJ-828 is battery pack newly designed specifically fot MagicShine bicycle lights. It offers higher quality and improved protection circuit for safe performance.Specifications:Capacitance feel inductive,Backlight Display5-speed battery power display,voltage display. Backlight Display. Allow you to monitor the battery voltage even in complete darkness.Battery：418650 Li-ion battery (8.4V4.4AH)Battery life:500 times cycleCharger：DC 8.4V/1.8ACharging time：3-3.5 hoursDischarging current：≤4AShell material：6061-T6 aluminum alloy,transparent PCSurface treatment：Premium Type III hard-anodized anti-abrasive finishWaterproof grade：IP67Size：486096 MMN.W.：330gWarranty: 180 days manufacturer warranty.