Vktech&reg; 12V 24V Digital Voltmeter Plug Red Volt Meter USB Car SUV Cigarette Lighter Power mode: cigarette lighter style Voltage measuring range: DC 8-40V ( DC 12V/24V Universal ) Display: 3-bits, red LED digital tube Function: Battery voltage monitoring,for 12V cars, SUV, 24V trucks, buses Size:75mm x 40mm