The cycling light feature an one-touch switch with 6 different lighting modes depending on your preference. Include full brightness, breath and 4 different flashing. Increased brightness by 60%, highly visible, further improving visibility and safety during riding. With a brake sensor that can adapt to angle correction and quick response and a light sensor that can adapt to brightness. In automatic mode, the smart bike rear light will turn on automatically when detect braking or riding in low brightness and turn off automatically when riding in high brightness. The tail light is built in 500mAh rechargeable lithium battery and stays lit for 8 - 40 hours. (Depending on the light mode). It comes with a type-C USB charging cable that charges from your computer, power bank or any device with a USB port. No need to buy additional batteries. The bicycle rear light comes with brackets. Saddle mounting bracket and adjustable silicone strap provided, make the bicycle rear light flexible to quick install or detatch on bicycles, seat post, seatbag. It can be easily disassembled in seconds without tools and it's very convenient to remove. Well-designed and compact designs make the LED taillight looks extremely cool and refined; Alloy material and solidly built make the flash light well quality and durable. IPX5-rated water resistant, ensure you safe ride in bad weather condition and environment.