Features: 1. Use: It is suitable for DC 4-100V, small in size, easy to install, and has a great effect on checking the voltage 2. 2. Large display. 3-digit LED digital tube, large numbers, quick and easy to read. 3. Cut the hole. The hole diameter is 30cm, easy to install 4. 4. Reverse connection protection. It protects when the wires are reversed or wrongly connected 5. 5. Compact design. Compact structure, small size, easy to carry, easy to store and carry 6. 6. Good quality. It is made of good quality plastic, durable and long lasting 7. Warm reminder: The input voltage cannot exceed 100V, otherwise the voltmeter will be damaged Precautions: 1. Due to manual measurement, please allow 1-3mm difference, thank you for your understanding 2. Due to the differences between different monitors, please understand that the pictures may not reflect the actual color of the item. Display Color: Green, Red, Blue Shell color: black Size: 3.38*3.38*1.8cm Line length: 20cm material: plastic Voltage: 4-100V Hole size: 3cm in diameter Minimal startup. 3.8V Allowable error: 1 input resistance. >100K Ohm Operating current: red <15mA, green <12mA, blue <12mA Refresh rate: Approx. 300mS/time show. 3-digit round LED nixie tube Working temperature: -10~65 quantity; 1 Package includes: 1*Voltmeter