1、[New Design] This LED digital voltmeter appearance using standard size, easy to install, volume 0.36 inch, range DC 0‑40V, 2 wires access, breaking the conventional voltmeter, is the latest design. 2、[2 Wiring] LED voltmeter is equipped with 2 wiring, wiring length is about 10cm/3.9in. 2 wiring use the highest input voltage can not exceed 40V, the use of voltage to be within 40V, otherwise there is a danger of burnout. 3、[Voltage Range] The voltmeter is 3V ultra low starting voltage, good stability. If the conditions allow, the recommended voltage range DC 4‑30V best, can work directly in 5V, 9V, 12V, 24V and other circuits, without voltage regulation. 4、[Reverse Connection Protection] The voltmeter has high measurement accuracy, and the power supply adopts polarity protection line, with reverse connection protection function, the line will not burn when connected in reverse. 5、[Use Way] voltmeter convenient access to the car, battery car, motorcycle car line. Used to monitor the battery voltage, battery voltage state in a timely manner, can also be used for other products voltage measurement purposes.