Lock Them On. Ride Forever. These lightweight aluminum lights lock to your handlebars and seat post with custom security bolts, and are guaranteed to last forever - If they're ever stolen, broken or water damaged, Fortified will replace 'em! Swap batteries on the go with removable, rechargeable USB batteries. 150 lumens in the front perfectly illuminates city streets, while 30 lumens in the rear keeps drivers alert. If you're looking to fully illuminate the darkest suburban paths and urban alleyways, try the Boost version with 300 lumens in the front and 60 lumens in the rear to keep drivers at a distance.