Acoustooptic Alarm: In the alert mode,there is any vibration it will alarm, 120 dB harsh sound will remind the owner and scare the thief Wireless Brake Taillight: When the bicycle brakes, the red light will light for 2 seconds Ambient Light Induction Switch: When you biking to the low light zone, the tail light will turn on automatically SOS Emergency Signal Light: In the non-alert mode, the bike tilt is greater than 45 degrees (Accidental crash can automatically enter the SOS rescue signal mode, or the bike toppled down to the ground at night),the light will automatically turn on the SOS function. Righting the bike then the SOS function will be automatically turn off. Intelligent Start and Stop: The bike is stationary for 15 seconds, the Taillight will shut down automatically. And When you use the bike, the light will recognize ambient light, the lights will automatically turn on when it in the darkness