Monitor and Record Power Usage of Home and Work Appliances with the Extech PM120 Power Monitor Monitor and record power usage of home and work appliances for energy conservation and cost reduction analysis with the Extech Power Monitor. This helps you determine if the electrical device should be replaced with a higher efficiency unit. The PM120 has a large dual LCD. The primary display shows Voltage, Current, Power, Power Factor and Frequency readings and the secondary display shows Total Time, Cost (cost of operation per minute, day or week), Set, or Energy. Design includes standard North American 3-prong electrical plug, front-socket connection, and backup battery that saves customized programs.