Ultra Bright COB LED Enhance Your Safety: With high lumen COB LED, Bike Brake Light, Daytime Strobe and Flashing Lights make you more visible in riding. Super bright braking light timely warn signals to road users while slowing down or stopping Wireless Anti-Theft Alarm Prevents Your Bicycle Stolen: Built-in high-decibel smart sensitive horn, the led bike tail light will make 3 levels alarm volume while bicycle is touched. Definitely noticeable to deter a theft from stealing your bicycle Auto ON/OFF Make Your Cycling Safety More Simple: Flashing lights and daytime strobe auto turn on when the rear bike light is moving or vibrating, otherwise the bicycle tail light go off. Dont worry about forgetting to turn on taillight in cycling Light Sensing Make Your Riding More Convenient: The bike tail light with intelligent sensor, rear flashing and breathing light turn on automatically in low brightness and turn off in high-intensity light. Save your time to switch the rear bike light Easy and Simple to Use: Safe USB rechargeable polymer lithium battery make the light battery life up to 40 hours; IPX5 waterproof makes the back light used even in bad weather; Saddle and seat post mounting make the taillight fit different bicycles