* The V stands for velocity and this tail light detects changes in riding speed and alerts surrounding traffic* High output surface mounted LED plus 2 5mm LEDs provide steady, Courtesy™, Superflash™ & V modes* Velocity Variation Technology™ accelerometer detects changing ride speed and alerts surrounding traffic with a four second burst of light* FL1 Tested - Run times: 8 hrs (steady–4 lm), 10 hrs (Courtesy™ -1-3 lm) and up to 36 hrs (Superflash™ -4 lm) * Provide 180° of visibility * Highly visible, even in daylight * Water resistance rated to IPX6 standard* 270 mAh lithium polymer battery charges in 2.5 hours with micro USB cable (included)* Smart Charging Technology™ with built in low battery indicator* Includes seat post, seat stay and clip mount for multiple mounting options* Mount it to your rear rack with the Rack Bracket (#3108) which is sold separately* 54 grams