With 7 colors, 18 different images and 2 modes to choose from, this unique bicycle wheel light will bring more fun and safety to your monotonous journey in the dark night whether you are alone or not. 550mAh lithium battery, long battery life; USB charging, 5-20 hours working time, saving your time to replace the battery. IP65 waterproof, can be used normally in rainy days (do not soak in water) . Thanks to this bright LED light, your bike wheel is always visible at night, making your riding safer. Easy to install, it does not affect the bike's center of gravity : more than 95% of bicycles are universal, such as road bikes, mountain bikes, BMXs, hybrid bikes and even children's bikes. Suitable hub diameter: 19mm~36mm. With no speed requirement, even if the bike parked, the bike wheel lights are just as beautiful. You can choose flashing or steady mode using the switch. It is also a great gift for your friends and family.