bicycle rear light smart auto brake sensing taillight saddle or seat mount cd05

like a car, it detects when you are braking to emit a bright light alerting others you are sing. under the weak light circumstance, this light sensing bike taillight brake sensor will automatically detect it and turn on for eye catching back rider and car driver. the bike smart brake light will be automatically switched off when detecting in no motion after 45 seconds. once touch it or detect the bike moving, the light will automatically turn on. it is more convenient to use and saves your valuable time. designed to endure any and all terrains and climates. waterproof for rainy days..syi