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. Time / date display, 12 / 24 hour system conversion. Snooze function, snooze time: 5 minutes. Capable of switching temperature display unit Celsius / Fahrenheit degree. Pedestal 180-degree revolve. Display accurate temperature readings in and outside of the car. Alert you to your car battery's voltage and its alarm sensor notifies you of excessive or under normal voltage operations. When the clock is powered by car cigarette lighter, there would be no backlight when it is powered by backup batteries. Car battery voltmeter. Powered by car cigarette lighter charger or 2 x LR44 batteries (NOT included). The LED backlight design allows you to accurately read the digits in the dark. Easy to install and use, a perfect accessory for your car. Also has the function of freeze alert. 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. Voltage:DC12-24V Base Diameter:4.5cm Power:0.6W Power cord length:Approx.150cm Temperature sensing line length:Approx. 200cm Stand-by power:2 x LR44 button cell(NOT included) Temperature measurement range: -10 - 50 degrees Temperature display resolution:1 degree Temperature accuracy:Plus/minus 1 degree Temperature measuring duration:60 seconds