Vktech 4x 18650 Waterproof Battery Pack Case House Cover For Bicycle Bike Lamp Can be packed into 4x18650 batteries and combined them to bicycle lights powered Output voltage: 8.4V, Input voltage: 8.4V Standard 5.5DC Interface (Case diameter 0.95cm, 0.5cm diameter within the interface) Cable: 60cm;(it have the USB cable) 1860 batteries are not concluded!