The Lezyne Femto Duo is an ultra-compact, two-in-one helmet light. Two-in-one safety light integrated into a versatile helmet mount. The Lezyne Femto front and rear light is coupled by a composite matrix junction. Compatible with nearly all vented-style helmets. The LEDs are housed in a super compact, lightweight and durable machined aluminium body. High-grade polycarbonate lenses provide side visibility and double as the power button. Front: 15 lumens, Rear: 7 lumens, two output modes. Easy to replace CR2032 batteries.