RECHARGEABLEPowered by built-in Li-Battery, USB charging, the wheel light could work continuously for 12 hours, save you from changing batteries all the time. 9 Color Modes: All functions are controlled by one button on the light. In the off state, short press to enter the light color selection mode; each press changes one color: red, blue, green,yellow, cyan, rainbow, 7 flashing colors. Long press any light mode to turn it off. In the off state, press and hold for 3 seconds to enter the mode with 18 kinds of patterns. WATERPROOFWith IP55 waterproof design, don't have to worry about bike wheel lights will be damaged while riding in rainy days, suitable for all kinds of weather. QUICK AND EASY INSTALLATIONSelect the appropriate size hub hub (included) to stick on the inner ring of the lamp. Circle the light in the center of the hub, then fasten the belt. No tools needed. UNIVERSAL BIKE WHEEL LIGHTSPerfect safety and decorative lights for almost any bike, including Road Bikes, Dirt Bikes, BMX Bikes, Hybrid Bikes, and even Kids Bikes (Hub Diameter : 19~36mm).