The Tail Light is built in rechargeable lithium battery. It comes with a charging cable that charges from your computer, power bank or any device with a USB port.
How to charge?
1. Connect the micro USB cable to the bike tail light micro USB input port.
2. Insert the other end of the cable into either an AC adapter(not included ) connected to laptop or computer or power bank usb port.
3.The power indicator of tail light has a red light when charging and the indicator will turn to be green when the charging is finished.