Features: Internal wiring applies the high efficient boostercircuit, working voltage is wide and can utilize the batteries inthe largest extent Waterproofing design Aluminum alloy casingCharacteristic: Multi-function Charge for bike light/headlamp: USBline connect with your computer,click the button,it will bright Use2x 2032battery pack,it can bright(not included) Package Included:1x LED Rechargeable Bike Light&Headlamp 1x Rubber O-rings