Function introduction: It is solar power driven. The light and vibrating sensor are built inside. It may be installed on the windows of different sides.with small size of 3.8*5.5*1.2cm During night driving, 4 LED light give off powerful penetrating flash of blue color, functioned as decoration or caution alert. When parked at night, 4 LED (red or blue color) flash automatically in a sequence, which serve as warning against crime. Product features: Built-in light sensor itself will decide to store solar power daytime and flash at night. Vibrating sensor trigger the 4 LED to flash at the same time during night driving and flash one after another during night parking. Installation notes: 3M adhesive is provided for free. You may choose your favorite positions. If installed on side windows, it helps to caution passer-by or passing cars when your car door opened. If installed on rear windows, it helps to caution the following car to keep a distance. If installed on front windows, it helps to warn against crime.