2 Wire Blue DC 4.0-30V LED Panel digital display Voltage Meter Voltmeter Opening size: 45.5mm * 26.5mmDimensions: 48mm * 29mm * 21mm /Range: DC4.0-30V 2 Line AccessDisplay: three 0.56 LED digital tubeDisplay colors: red / green / blueRefresh rate: about 500ms /Measurement accuracy: 1% (+ / - 1 words)Supply voltage: DC4.0-30V (measurement collinear)