4.5-30V DC Two-Wire 0.56" 3 Digit Blue Panel Mount LED Digital Voltmeter Voltage Meter This voltmeter can be used to measure the battery and charging voltage in cars, trucks, motorcycles, ATVs, RVs and other applications requiring voltage measurement from 4.5V to 30V. The two-wire design simplifies interconnection. The Blue wire connects to the battery's positive terminal and the black wire to negative (ground). Additional circuitry or a sense wire is not needed. .
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