Acceleration sensor - when speed is reduced by more than 1.6 m/s (5.76 km/hr or 3.58 mph) an additional LED is switched on Light guide for increased visibilty and safety Brake light is 3 times brighter than normal output in steady mode Additional optic in front of led at lower end of light guide Memory function remembers the last mode used Fully USB rechargeable Bracket with flexible mounting option .20 LUX 7 Modes Run time on eco = 36 hrs Run time on high steady = 10 hrs