Sleek visibility designed to integrate seamlessly with compatible giant and liv helmets the numen alumbra tl is the slimmest and most lightweight helmet attachable tail light and features a unique quick magnet mount design for easy on and off as well as a built in low power indicator. Features maximum output to 20 lumens ansi certified lumens and runtime ipx4 water resistant power status indicator alerts remaining run time before powering off light memory mode compatible with rev comp compel roost strive lanza coveta rev liv comp and luta series helmets specifications size 54x13x27mm weight 17g without mount colors black max output 20 lumens hl runtime high 2.5hrs 20lm low 6hrs 10lm high flash 7hrs 20lm low flash 24hrs 5lm battery li ion polymer battery 250mah water resistant ipx4