Product OverviewBT20 is a specially designed professional bicycle light for bicycle enthusiasts. It delivers a max 750-lumen output. Employing the pioneering dual distance beam system, the upward beam of BT20 is refracted by the lens, forming an auxiliary beam in the front area of the wheels where ordinary bicycle light can not reach. With its advanced aspherical light cup design and broad beam distance up to 156m, it can bring the users a broader view in the night riding. The active fashion style of BT20 conforms to the aerodynamics design with small 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.