High Accuracy High accuracy percentage (1 digit). The ground wire of the test end and the power terminal is the same wire; fast refresh about 500MS/hour. Connection Protection With reverse connection protection. If the positive and negative poles are reversed, the LED display will not be burned out. Built-in Shunt The 10A voltage and current meter itself has a built-in shunt. 2 Colors to Distinguish Display voltage and current simultaneously in different colors, red for voltage, blue for current (current is measured in the negative rail). Wide Application KeeYees DC voltmeter has convenient connection and wide application, for example, it can be applied to monitoring storage battery, adjustable DC power supply or other device's voltage and current changing status. Current test range: 0-10A Power supply range: DC 4-30V (Note: If the voltage exceeds 30V, an independent external power supply is required) Voltage error: 0.1% Current error: 1% Working current: