2-Pack P3 P4400 Kill A Watt Electricity Usage Monitor Includes 2 P3 P4400 Kill A Watt Electricity Usage Monitors Large Lcd Counts Consumption By The Kilowatt Hour Connects To Household Appliance & Assesses Its Efficiency Calculates Electrical Expenses By The Day, Week, Month Or Year Checks The Quality Of Power By Monitoring Voltage, Line Frequency & Power Factor