BT20 is the newest extension of lights by Fenix designed for bicycle enthusiasts. It delivers a max 750-lumen output and employs the pioneering dual distance beam system. This beam system allows the upward beam of the BT20 to refract by the lens, forming an auxiliary beam in the front area of the wheels where ordinary bicycle light can’t reach. With its advanced a spherical light cup design and broad beam distance it can reach up to 156m. The active design of the BT20 conforms to the aerodynamics design with less wind resistance and fast heat dissipation; it is quick to attach and detach using O-ring mounting straps sized for 20mm-35mm handlebars; moreover, the direction of the headlamp can be adjusted freely, which brings you more convenience. Powered by two 18650 rechargeable Li-ion batteries or four CR123A Lithium batteries, BT20 features four brightness levels and one variable frequency flashing mode, which satisfy your various lighting needs such as commuting, urban utility, cross country, down hill, etc. *Limited Lifetime Guarantee supported by Fenix Lighting US and cannot be guaranteed to cover all Amazon retail partners.