EASY AND SIMPLE MOUNTING SYSTEM: With saddle rail and seatpost mounting options, the bicycle rear light can most fit any bicycle. With the Independent design of bracket and taillight, it's very convenient to twist the light in & off the base cap for charging.ULTRA BRIGHT AUTO BRAKE LIGHT: With the super bright braking light, the bike rear light is highly visible from a distance while slow down or stopping. The brightness of the brake light is 3 times brighter than normal when the brake light is working and really catch road users attention to enhance your safety.LIGHT SENSING & AUTO ON OFF : Build in smart light and motion sensor, the flashing and breathing lights will automatically turn on and turn off according to light intensity and motion state. They will automatically turn on when detect any movement or vibration and shut off when there is no movement or vibration in low brightness. They will automatically turn off in high brightness.USB C RECHARGEABLE & LONG BATTERY LIFE: With safer polymer lithium battery and energy-saving designs, the rear bike light run time can be up to 50 hours. With Type-C charging port and USB C charging cable, the bike back light can be easily charged via current universal computers, chargers or power bank.HIGH LUMEN COB LED & 3-LEVEL ADJUSTABLE BRIGHTNESS: With quality COB led, optical lampshade and wide light angle design, the smart bike tail light will make you more visible in your riding and add an extra layer security in your cycling. With the adjustable brightness function, it's convenient for you to tailer the appropriate brightness to your needs and individual situation.