1. Wide Measurement Range: The DROK plug-in voltage monitor measures AC 80-300V (110V, 220V), with low power consumption of less than 1W (approximately every 1200 hours it consumes 1 kilowatt-hour). 2. Adjustable Potentiometer: An internal potentiometer allows for precise accuracy adjustment. Simply use a screwdriver to open the outer casing and adjust the potentiometer with a small screwdriver. Turn the potentiometer counter-clockwise for overvoltage; if the displayed voltage is too low, turn the potentiometer clockwise. 3. Flat Plug: Designed with a flat plug, this voltage tester instantly detects and measures the current voltage by plugging into a power outlet or other wall outlet type. Simple and easy to use, it allows you to check the health of device power to prevent low-voltage damage to your valuable appliances. 4. LCD Display: Featuring a premium LCD digital display with blue backlight, this voltage monitor is easy to read even in low light. It can also be used as a voltmeter and a night light. Wide Application: Ideally suited for measuring AC voltage in homes, offices, industrial and mining enterprises, etc. (Keep children away from the product & do not use the product in a damp environment).