The moon comet mk ii rear light has a compact light and easy to fit unit offering a light output of up to 50 lumens for great visibility the lithium polymer battery is rechargeable with an indicator light to let you know when it is charging fully charged or has low battery this moon rear bike light also offers you a 300 degree total light angle to deliver side visibility for increased safety the 8 different modes allows you to get the best light for you ride offer