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 monitor voltage and help prevent issues with appliances. You can use this item 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. It enables you to plug in RV to monitor voltage for preventing issues with appliances. Keep children away from the product. Avoid using the product in a damp environment. 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 it 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, compatible with countries such as Indonesia, Germany, France, Italy, and others Material: ABS Color: White Package Contents: 3 x Voltage test meters Note: Light and different displays may cause the color of the item in the picture to vary slightly from the real thing. Measurement may have an error of +/- 1-3cm.