This instrument is a multifunctional meter allows you measure the amount of electricity used by an appliance. It is ideal for use with large aooliances such as air conditioner, refrigerator and office machine. It allows you to enter two electricity prices for two different time periods to calculate the total cost of an applicance's power cinsumption, and to monitor the electricity usage. It can detect energy overloads and record the highest amperage, voltage and wattage. To use the instrument, first you should perform the settings of the instrument, then plug the instrument to a standard AC outlet on wall, finally connect the plug of the applicance to be monitored to the socket of the instrument.