Multiple Brightness & Brake Sensing: Our taillight offers 3 brightness modes to adapt to various riding environments. When braking, the light remains on for 3 seconds to alert vehicles behind, enhancing safety and improving your cycling experience. Dynamic Modes & Easy Installation: Choose from 4 dynamic lighting modes: (1) Normal Flash, (2) Breathing Flash, (3) Fast Flash, (4) Steady On. Designed for versatility in day and night conditions. Installs quickly using the included metal under-seat clamp or rubber mount. Compatible with road, mountain, cruiser, and commuter bikes. Extended Battery Life & Power Indicator: Powered by a 400mAh Li-ion battery for long-lasting performance. Features a 4-level blue LED power indicator, each representing 25% charge level, so you can easily monitor battery status. Group Sync Functionality: While in motion, the taillight can automatically sync blinking patterns with other compatible lights nearby. Activation requires a double-tap by the user. Enables synchronized lighting for group rides, creating a unified visual signal among riders using the same model. Smart Auto On/Off & IPX6 Waterproof: Equipped with motion and light sensors for intelligent operation. Automatically turns off after 30 seconds of inactivity and reactivates when movement is detected (applies to modes 1 and 2). For constant visibility during daylight, use modes 3 or 4 to override the light sensor. Brake sensing works in all modes. Rated IPX6 for reliable water resistance.