Makerfire Functional Car LCD Clock Alarm Calendar Inside Outside Thermometer Voltage Meter Voltmeter DIY Time/Date display, 12/24 hour system conversion Alarm function Pedestal 180revolve Two colors of backlight for choice when the clock is powered by car cigaretee 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 Size: 9.3cm x 6.5cm x 6cm