Yosoo Multi-functional 12V Car Auto LCD Digital Clock Thermometer Temperature Voltage Meter Monitor (Green) This Car Voltage Meter Clock Thermometer is a multifunctional clock with 4 in 1 function, including time, thermometer, voltmeter and backlight.It can inspect your automobile at real time effectively, there is alarm lamp to remind you to avoid icing may cause damage to your car as temperature lower freezing point. There are alarm voice and lamp to remind you to cheeking the storage battery as the voltage is excessive to too low. You can maintain your automobile by the real time data of voltage Special function : Time display (12 / 24hour), date display, dual temperature display, alarm clock, snooze function, frost alarm function, automobile storage battery voltage indicator function, LED backlight Two colors blue / green of backlight for choice when the clock is powered by car cigarette lighter, there would be no backlight when it is powered by backup batteries. Alert you to your car battery's voltage and its alarm sensor notifies you of excessive or under normal voltage operations When it connects with car, its back light is light up and all the contents (including the time, temperature and volt) will be displayed on the LCD screen