The femto duo is a two in one safety light integrated into a versatile helmet mount evolved from our popular femto series the unit features a front and rear light coupled by a composite matrix junction thats compatible with nearly all vented style helmets the leds are housed in a super compact lightweight and durable machined aluminum body and the high grade polycarbonate lenses provide side visibility and double as the power button the front emits 15 lumens while the rear puts out 7 lum