This is a rechargeable digital clock with an auto backlight. It can be charged via a solar panel on the back or via USB. If the battery runs out, it will operate using a button cell battery. It can be installed neatly without any unsightly power cords. The backlight can be switched between blue and green. It automatically turns on when it detects vibration at night and turns off after a while when the vehicle stops. Made in China. We have tested its operation just in case. Please note that the packaging may be damaged. 8cm x 3cm x 3.5cm Weight: 55g