The monitor can be widely applied in AC 80-300V mains measurement, such as office, factory, laboratory, household, and so on. You can use this item in RV to view voltage to prevent issues with appliances. It can be used to monitor the voltage of other appliances; when the volt gauge displays too high or too low voltage, you can selectively turn off your appliances or equipment to help prolong their life. Available Range: Widely applied in AC 80-300V mains measurement. Enables connection to RV for voltage monitoring to prevent appliance issues. Keep children away from the product. Avoid using the product in damp environments. Potentiometer Adjusting: Use a screwdriver to open the outer covering, then adjust the potentiometer with a small screwdriver. Adjust the potentiometer counter-clockwise if the voltage is excessive; if the display voltage is too low, adjust clockwise. Measuring accuracy: +/-1.5%, +/- 2 digits Measuring range: AC 80 - 300V (110V, 220V) Consume power: less than 1W (approximately 1 kilowatt-hour every 1200 hours) Number of digits: 3 digits Plug Type: EU Plug, suitable for use in Indonesia, Germany, France, Italy, and other compatible regions Material: ABS Color: White Package Contents: 3 x Voltage test meters Note: Light and display differences may cause slight color variation between the image and the actual item. Measurement allowed error is +/- 1-3cm.