2 in 1 Bike Taillight:Multi-function anti-theft taillight designed with bicycle alarm, COB LED and 200 degree wide angle design, the LED bike light will make you more visible to other bike riders. the road in darkness or daylight. We will keep you safe at all times. Smart Brake Sensing Technology:Designed with the brake sensor, the ultra-bright auto brake light turns on automatically after braking. The bicycle light is super bright and very visible from afar, it really attracts attention to improve your safety. 115 dB extremely loud: The bicycle security alarm can emit a loud sound to attract people's attention. 115 dB loud can scare away thieves effectively, it can also be used as a bright taillight, smart remote alarm and electric doorbell. Two Mounting Methods for All Types of Bikes (Refer to Instruction Manual for Details) IP65 Waterproof & USB Rechargeable: IP65 Waterproof Bicycle Tail Light water from all angles. The built-in 800mAh lithium-polymer battery comes with a USB cable that charges from your computer, wall charger, power bank or any other device with a USB port. After a 3-hour recharge, the tail light can work for 20-40 hours in 3 different modes. Easy to assemble and disassemble:Saddle mounting bracket and adjustable silicone strap provided make the bicycle taillight flexible for quick installation or locking onto bikes, seatposts, seat tube mounts. Very convenient to unscrew from the mounting cap for filling.