Bestpriceam DC 4.5-30v 2 Wire Blue LED Panel LED Display Voltage Meter Voltmeter Minimum input: DC4.5(Below this voltage,it will show measurement inaccurate, or don't show). Maximum Input: DC30V(please do not exceed 30V, otherwise, the meter would be damaged.). Measuring Range: DC4.0-30V, Refresh speed: about 500ms/each time. Size:4.8cm x 3cm x 2.2cm - 1.89inch x 1.18inch x 0.87inch. DC4.5-30V 2 Wire Blue LED Panel LED Display Voltage Meter Voltmeter