USB Rechargeable Rear Lightrear bike light built-in 330mAh rechargeable lithium battery, can use 12 hours in high lightness mode with only 2.5 hours charging.5 LED Lights with 4 Brightness Modes4 Brightness Modes, Strong light, high frequency cycle, flash, single point cycle, slow flash. Only takes 2.5 hours to fully charge and has a Runtime of 12 hours in different modes.Impact Resistance and IPX4 WaterproofBicycle Taillights made of superior ABS material, excellent impact resistance, heat dissipation and corrosion resistance. IPX4 waterproof function can prevent water from entering at any angle.Install in Seconds & Compact DesignNo tools is required and install in seconds. 4 buckles silicone straps and fit most sizes of seatpost. Compact design makes it easy to take.Safty RidingThe bike taillights emit a striking wide-angle beam that can be seen from a distance, so you dont have to worry about being knocked over by others. It can be used for outdoor sports, such as cycling, running, hiking, camping, etc.