Feature:1. High Accuracy: The refreshing speed is about 300mS once, which ensures high accuracy in volt measuring.2. Measure Range: With 030V measurement range, also enables low start working voltage of 4.7V minimum.3. Safer Working: Reverse connection protection will get you rid of burning when it's reversely connected.4. Clear Display: Using 3 digit 0.36in LED digital tube, the clear display will show the real time voltage.5. Easy to Install: 3 wire design largely simplifies the wiring, which can be easily completed in minutes.Specification:Item Type: Digital VoltmeterMaterial: PCBFunction: For DIY production. Measuring Range: 0.00V-30.0V. Power Supply Range: DC 4.70-30.0VMaximum Input: DC 30.0VAllowable Error: 1%; when greater than or equal to 10V, the error is 0.3V; when less than 10V, the error is 0.10V. Input Impedance:> 100K ohm. Working Current: Green, <18mA. Refresh Speed: About 300mS once. Display Mode: 3 digit 0.36in LED digital tube. Lead Length: Approx. 15cm / 5.91inInstallation Hole: Hole Pitch: Approx. 28mm / 1.1in, Hole Diameter: Approx. 2.8mm / 0.11inWorking Temperature: -10~65.Package List:2 x Digital VoltmeterNote:Input voltage higher than 30V may be permanently damaged.