SMAKN 0.56" 2 Wire Red Dc 4.0-30v LED Panel Digital Display Voltage Meter Voltmeter Automatically Adjust the Precision Measure voltage: DC 3.3-30V (two wires Access) Measurement precision:0.01V(3-10V); 0.1V (10-30V) Display: Three 0.56" digital LED Tube Display color: RED Operating temperature: -10c to 65c