Kinfire K40 Waterproof 8.4V 4400mAh 2-in-Series 2-in-Parallel 4 x 18650 Battery Pack - Black
Waterproof Rating: IP68; Power supply for bicycle light or headlamp; 2-in-Series 2-in-Parallel; Charging time: 3~4 hours; Universal for Cree XM-L T6 / L2 / U2 / Z7 / R5 bulb headlight or bicycle light; Provide high mode light 4.5~5 hours for 3 x CREE XM-L T6 and high mode light 3 hours for single CREE XM-L T6 or SSC Z7 bulb; US plug charger voltage: 100~240V; Electric current: 1000mA