Feature: 1. High Accuracy: This is a high accuracy DC digital display voltmeter head with a refresh rate of about 300mS once. 2. Basic Specifications: The measuring range of the DC digital display voltmeter is 0V‑30V, and the low start working voltage is 4.7V. 3. Reverse Connection Protection: This is a DC digital display voltmeter with reverse connection protection, which will not burn when connected reversely. 4. LED Digital Tube: This is a DC digital display voltmeter head with 3 Digit 0.36in LED digital tubes. 5. Light Weight: This is a small and light digital display voltmeter head, which is very easy and convenient to carry. Specification: Item Type: Mini Digital Voltmeter Material: PCB Purpose: DIY Production Measuring Range: 0.00V-30.0V Power Supply Range: DC 4.70-30.0V Maximum Input: DC 30.0V Allowable Error: ±1%, when greater than or equal to 10V, the error is ±0.3V, when less than 10V, the error is ±0.10 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 / 5.91in Installation Hole: Hole Pitch: Approx. 28mm / 1.10in, Hole Diameter: Approx. 2.8mm / 0.11in Working Temperature: -10℃~65℃. Package List: 2 x Module Note: Input voltage higher than 30V may be permanently damaged.