1. Description of the intelligent brake taillight: The bicycle taillight is equipped with a highly sensitive brake sensor, which will automatically light up when braking. The bicycle taillight is bright enough to be clearly visible from a distance, making cycling safer. 2. Ambient light sensor: The bicycle taillight with a built - in light sensor has 4 intelligent modes. The light will not flash during the day, and it will automatically turn off after 3 minutes and turn on again when it is vibrated. 3. USB rechargeable and IPX - 6 waterproof: The bicycle taillight can be charged via USB, and it comes with a USB data cable (no adapter is required). After being fully charged, the light can be used for about 13 - 30 hours depending on the mode. In addition, the light has an IPX - 6 waterproof function, which can protect the light from damage in rainy days. The USB port is fully covered, making it convenient to use in any weather. 4. Suitable for most bicycles: This bicycle light can be easily installed without tools and is suitable for various types of bicycles, such as road bikes, mountain bikes (MTB), and commuter bikes.