12V car digital voltmeter gauge is waterproof, mini size with 3-digit LED Digital Display. | This voltmeter measures voltage DC 5V-28V, which is suitable for various power supply. Please note that this voltmeter cannot be connected to AC 220V. | With reverse connection protection, red and black wire, red is for positive of the power supply while the black is for the negative side, simple connection, easy to use. | Car voltmeter digital display "LLL" when the voltage is lower than measuring range; displays "HHH" when the voltage is higher than the measuring range, when the voltage is lower than 11.5V or higher than 19.8V, the voltmeter will flash continuously to warn. When the car is charging or discharging, you can know the car status in time through the voltmeter. | LED display voltage meter suitable for cars, motorcycles, bikes, substation automation, distribution automation, test equipment, voltage regulator, and so on.