This smart brake-sensing bicycle taillight features a smart light/vibration sensor, a USB-C charging port, IP66 waterproof rating, and four lighting modes. The built-in light/vibration sensor uses intelligent sensing technology to automatically detect ambient light, illuminating when entering tunnels or at night, and automatically entering sleep mode during the day. A vibration wake-up function ensures the taillight illuminates instantly while riding, eliminating the need for manual switching. When decelerating, the sensor emits a bright flashing light. The taillight boasts a brightness of 52 lumens and offers four modes: slow flash, breathing light, fast flash, and constant light, with automotive-grade intelligent automatic adjustment. It has an IP66 waterproof rating, a built-in 600mAh battery providing up to 70 hours of battery life, and supports USB-C fast charging, fully charging in 2-3 hours. A three-color indicator light displays the battery level in real time.