Feature: Reverse Connect Protection Range: DC4.5-30V (No need aditional power) Display: Three 0.36 /0.56 LED digital tube Display color: RED/ BLUE /GREN Refresh rate: about 500mS / times Input: DC voltage (<2 times the range) Resolution: 1% +1 digit Power Supply: DC4.5-30V (with the input common-line) Operating temperature: -10c~ 65c Working current: <20mA Baby Description: 1. the voltmeter wiring is simple, only need to pick two lines, the table reversal protection, reverse does not burn. 2. the voltmeter start voltage is low, the red just 3.2V, just 2.7V Green, the blue just 3.0V will be able to measure correctly, start with the price of two-wirevoltmeter voltage is the lowest anywhere in the world. This will greatly facilitate the use of the lithium battery, 18650 battery users. When the voltage is lower than 3.5V, the display brightness diminishes, but does not affect the correct measurement. 3. in order to achieve optimum measurement accuracy, the voltmeter will be different according to the measured voltage automatically move the decimal point position. Measure the voltage below 10V, displayed after the decimal point two; 10V voltage measurements displayed after the decimal point one. That is able to take care of the battery user needs, but also cater to the needs of the higher voltage measurement on the measurement accuracy. 4. the voltmeter can be used for motorcycles, cars and other monitoring battery voltage, timely grasp battery status. Other voltages can also be used formeasurement purposes.