Moon arcturus auto pro rear lightthe moon arcturus auto pro rear light is an attractive light that will fend off any rear approaching vehicles or other cyclists. With 7 modes, you are able to cycle through them all until you find the one that best suits the conditions you are riding in or the remaining battery life.producing 100 lumens, this is bright for a rear light and combined with an integrated light sensor, the arcturus is ideal for the daily commuter.featuresconstruction engineering grade plastics and a cnc machined aluminium heat sinkleds 1 piece rectangular led chipbrightness 100 lumensbattery rechargeable li ion 3.7v 650 mahbattery life indicator yesmounting simply rubber strap fitmentlight modes 7 modeswater resistant yesfeatures auto fully charged cut offweight 30gbuy moon accessories from chain reaction cycles, the world's largest online bike store.