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 only one button on the light. In the off state, short press to enter to the mode of select the color of the light, per press change one color: red, blue, green, yellow, cyan, rainbow, 7 colors flash. Long press under any light mode to turn off. In the off state, press and hold for 3 seconds to enter the mode with 18 kinds of patterns with automatically changing color.WATERPROOF: With IP55 waterproof design, Don't need to worry about the bike wheel lights will be damaged when riding in rainy days, suitable for all kinds of weathers.FAST AND EASY INSTALLATION: Select appropriate sized hub pad (included) to stick on the inner ring of the light. Encircle the light in the center of the hub, and then buckle up. No need for tools.UNIVERSAL BIKE WHEEL LIGHTS: perfect safety warning and decoration lights for almost all bikes including Road Bikes, Dirt Bikes, BMX, Hybrid Bikes, and even for children bikes (Hub Diameter: 19~36mm).