The Bell toggle 350 convertible light set offers flexibility and power in a "to be seen" light set. The toggle 350 light set offers both steady and battery-saving flash modes and the dual white/red LEDs allow the same light to be used on the front or rear of the bike. No tools needed --Silicone straps secure the lights anywhere -- handlebars, forks, seat post or seat stays. Both lights come with four Cr2032 batteries pre-installed so they're ready to use right out of the package. And because all Bell lights are tested and rated to industry-recognized fl-1 standards, you can rest assured they perform as advertised. Headlight specifications: brightness: 33 lumens; run time: 8 hours (steady)/16 hours (flash); beam distance: 20 feet. Tail light specifications: brightness: 4 lumens; run time: 16 hours (steady)/25 hours (flash); beam distance: 6 feet.