Function: 1. The power meter can only measure the active power, it does not display the apparent power. If you measure the power of the DC-AC inverter, make sure it is pure fala sine wave. Otherwise, the meter may burn or melt. 2. Its clear large screen can display voltage/current/active power/cumulative electricity/frequency/power factor simultaneously. 3. The backlight can be turned on/off manually, making it easy to read in the dark or in strong light. 4. When the set power value is exceeded, the backlight and power digits will start flashing. 5. This button is used to control the backlight, reset energy data or set battery alarm thresholds. Specification: Item Type: Power Monitor Material: GFR nylon Purpose: This product can measure voltage, current, power, electricity, frequency and power factor; Voltage: 110250V Current: 0,00100A Power: 0,0022000W Power factor: 0,000,99 Electricity: 0,0199999 kWh Frequency: 50 Hz/60 Hz Product Size: Approx. 90x54,5x28mm / 3,5x2,1x1,1 inch List of packages: 1 x Power Monitor 1 x English Manual