Features: 1. Use: It works for DC 4-100V, mini size and easy to install, work great for checking voltage. 2. Large display: 3-digit LED digital tube, large numbers, quickly and easily read. 3. Opening hole: The opening hole diameter is 30cm, easy to install. 4. Reverse connect protection: It can be protective when connect the wire inversely or wrong. 5. Compact design: It is compact, mini size and portable, easy to store and carry. 6. Good quality: It is made from good quality plastic, which is durable, long lasting. Specification: Display color: greenredblue Shell color: black Size: 3.38*3.38*1.8cm Wire length: 20cm Material: plastic Voltage: 4-100V Opening hole size: diameter 3cm Minimum start: 3.8V Permissible error: ±1% Input impedance: 100K ohms Working current: red 15mA, green 12mA, blue 12mA Refresh rate: approx.. 300mS/time Display: 3-digit round LED digital tube Operating temperature: -10℃65℃ Package includes: 1 x LED voltmeter Warm tips: The input voltage can not exceed 100V or the voltmeter will be damaged. Notes: 1. Please allowed 1-3mm differences due to manual measurement, thank you for your understanding! 2. Due to the difference between different monitors, please understand that the picture may not reflect the actual color of the item.