Check the listing for details. 3PCS RED, GREEN, BLUE Digital Voltmeter Car Motorcycle Voltage Volt Panel Meter. Condition: New. Listed at 2.50 USD. Current: 5-15mA Display mode::Three digit 0.36''LED digital tube Description: This voltmeter's wiring is simple, it only need to connect two wires,the red wire is to connected to positive pole, the black wire is to connected to negative pole. There is protection when the wires aren't correctly connected, the electric circuit won't be bumed. This voltmeter doesn't need external drive working power, it can work with measuring voltage, the working voltage's range is 4.5-30V. To reach the best measurement accuracy,this voltmeter is auto range it will automatically move the decimal point's position according to the different measuring voltage. When it measures the voltage below 10V,it will display two places after decimal point. When it measures the voltage above 10V, it will display one place after decimal point.