Bike lights allow the rider to be seens whilst riding, and aid the use of reflective equipment. Additionally in poorly lit areas they can also allow the rider to see. They are broadly categorised into commuter and off road bicycle lights. Commuter bike lights rely on some ambient light from street lights and cars to see ahead, where as off road bicycle lights are designed to be used in total darkness. There are a variety of usb, li-ion and standard battery powered lights on the market for different uses and price points.