Feature:1. The voltmeter has simple wiring, only two wires need to be ed, and there is anti ion protection in the voltmeter, which does not burn.2. The starting voltage of this voltmeter is low. It only needs 2.5V for red, 2.7V for green and 3.0V for blue. The starting voltage of two-wire voltmeter at the same price can be called the lowest in the world. This will greatly facilitate the use of lithium batteries, 18650 batteries and other users. When the voltage is lower than 3.5V, the display brightness will darken, but it will not affect the correct measurement.3. In order to achieve the best measurement accuracy, the voltmeter will automatically move the decimal point according to different measured voltages. When measuring the voltage below 10V, two digits are displayed after the decimal point; When measuring voltages above 10V, one digit is displayed after the decimal point. It can not only meet the needs of battery users for measurement accuracy, but also meet the needs of measuring higher voltage.4. The voltmeter can be used to monitor the battery voltage of motorcycles and automobiles and master the battery status in time. It can also be used for other voltage measurement purposes. Specification:Measuring range: Red DC2 5-40v, blue 3.0-40vOpening size: 34.5x18.5mmMinimum input: below the minimum voltage, the measurement is inaccurate or does not displayMaximum input: DC30V (higher than this voltage, there is a risk of burning)Lead length: 20cmAllowable error: accurate to 0.01V below 10V, accurate to 0.1V above 10V, allowable error 1% (+ / - 1 word)Display mode: three digit 0.36 " LED nixie tubeDisplay color: Red, Green, BlueRefresh speed: About 200ms / timePower supply: no power supply is requiredConsumption current: less than 20mA, generally 5-15maOperating temperature: - 10 ℃ - 65 ℃Overall dimension: length 37x width 23x thickness 15mmNet weight: 15gGross weight: 20g (including packaging)Color: Red, BlueDecoration and construction content: installation worksMeter type: Standard watt hour meterPower circuit: DC meterWorking principle: electronic watt hour meterNote:Due to the different monitor and light effect, the actual color of the item might be slightly different from the color showed on the pictures. Thank you! Please allow 1-2cm measuring deviation due to manual measurement. 1 xVoltmeter