Enfitnix Cubelite II Rear Light INTELLIGENT LIGHT SENSOR: during the day, it turns off automatically and driving at night turns on automatically. In order to avoid the influence of the car light at night, it automatically turns off after being irradiated with strong light. BRAKE DETECTION LIGHT: Not only is the braking mode sensitive, but it will also automatically change the braking mode, calling attention, improving safety LED LIGHT : The COB LED light source is bright but not dazzling, so you can drive in safe way IPX5 classification WATERPROOF: prevent water intrusion. You will continue to use it even if heavy rain falls. EASY TO INSTALL: No installation tools needed, easy to install and disassemble, fits most road bikes and mountain bikes.