Serious road riders put in serious miles. Most of those miles occur in the daytime, when bright ambient conditions mean you need huge lumens numbers to be seen by motorists. But there's no reason a super-bright taillight can't look the part on the fastest road bikes. You invest in the best road bike technology--you deserve an equally fast taillight. Packing a huge punch with 250 lumens, the Flux 250R taillight is visible at more than 1 mile (1.5 km) in the brightest daytime conditions. Here in Morgan Hill, California we get those conditions all the time, this is the taillight we made for ourselves, and for you. - Designed to fit round and D-shaped seatposts. - Disco Flash mode: 250 lumens for 8:00 hours - Eco Flash mode: 25 lumens for 60:00 hours - Hybrid spherical lens and Fresnel lens over three high-power LEDs to send lumens for mile, or kilometers. - IPX7 waterproof means this light will be there when you need it, even in the hardest rain. - Includes 3 different size EPDM o-rings to fit a wide variety of seatposts. 2 o-rings included per size for spares. - Massive 1000mAh battery recharges via included micro USB cable in 2:15 hours. - Overmolded bezel for excellent side visibility. - Power Flash mode: 250 lumens for 8:00 hours - Steady High mode: 100 lumens for 3:00 hours - Steady Low mode: 25 lumens for 12:00 hours - Three CREE XBD 901 LEDs for maximum brightness and efficiency.