Hittime 2 Wire Blue LED Panel LED Display Voltage Meter Voltmeter Brand new and high quality. Measuring Range: DC4.0-30V. 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.). Display: three 0.56LED digital tube. Display colors: blue. Refresh speed: about 500ms/each time. Allowable error: 1% (+ /-1). Power supply:No need power supply. Current consumption: Less than 20 mA, general 5-15 mA. Working temperature: -10 ~ 65 . Size:4.8cm x 3cm x 2.2cm - 1.89inch x 1.18inch x 0.87inch.