Nuther Dinotte user here using a pair of 400L, one helmet mounted, the other on the handlebars. Lights up the dark German forests on my route like a mofo. As Schwinnrider says, they're on the pricey side but hella worth it. A set of 400L on the front is plenty if you commute on streets/paths. If you're like me and commute on trails under a forest canopy with no lighting then a set up with some lumens is whats needed.