Feature:1. No speed is required, will constant lighting when power on.2. Separate design, easier to install, and suitable for mountain bikes and children\u0027s balance cars.3. Waterproof design, you can usually ride in rainy days.4. Used to install children\u0027s bike wheel hubs for safe driving at night.5. Easy to install and remove. Automatically color changing.Specification:Installed in the center of the wheel, won't affect the center of gravity of the bicycleFeatures:No speed is required, will constant lighting when power on.Separate design, easier to install, and suitable for mountain bikes and children's balance cars. Waterproof design, you can usually ride in rainy days.Used to install children's bike wheel hubs for safe driving at night.Easy to install and remove. Automatically color changing.Specifications:Diameter not exceeding 30mm is availableMaterial: PCBattery Capacity: 300mAh Li-Battery (USB rechargeable)Installed Diameter: Less than 30mm (Especially recommend for kids balance bike)Work Time: 8-12 hoursItem size: 82 * 82mm / 3.2 * 3.2inPackage size: 86 * 86 * 37mm / 3.4 * 3.4 * 1.5inPackage weight: 70g / 2.5ounceNote:No vibration is felt after 5 seconds of power on, and the light turns off intelligently.In the process of use, if the light do not feel vibration for 35-40 seconds, the light will go out automatically, and the light will turn on intelligently when it vibrates again.Packing List:1 * Bicycle Wheel Light1 * Set of Rubber Gasket1 * USB Charging CablePackage List:1 * Bicycle Wheel Light1 * Set of Rubber Gasket1 * USB Charging Cable