1 auto-sensing switch control, and dynamic light perception of double light switch only at night, indoor, low light and the car will move off the dual case. 2. Waterproof grade: IP55 3 7-color light from the 16 double-sided LED, mounted on the bicycle on the wire, installation is simple, there are 32 kinds of changes in patterns. 4 for 20-inch and 20 inch and above all the bikes, including disc brakes and ordinary V-brake. Please note that bike itself, the length of the wire radius, as long as greater than or equal 14CM like installed. Clamp and housing are PC. PC is a very strong material toughness. ! 5 speed problems: speed requirement is 25 yards out of the whole map. Up to 15 yards on the very beautiful! 10 yards or less can be used as night riding safety lights, very bright! Stronger than the average tail Material: PC Size: 15X3.8X1.5CM Battery: 3 X AAA Battery Package Include: 1 X bicycle 16 led light 3X AAA Battery