Shows the operating costs of yourhousehold appliances.Accurate within 0.2%.Large LCD Display.Calculates cost and forecastsby week month and year.Built-in battery backup. Displays eight critical units of measure. Calculate your cumulative electrical expenses and forecast by the day week month even an entire year. Also check the quality of your power by monitoring Voltage Line Frequency and Power Factor. Now you"ll know if it is time for a new refrigerator or if that old air conditioner is still saving you money.