The patented SmartPlug lets you upgrade any hot water recirculation pump with a power cord to "Smart" operation. Simply connect the SmartPlug to any 110V power outlet then plug the circulator power cord into the SmartPlug. Using a sensor that mounts to the hot water supply pipe, the SmartPlug will record the daily hot water usage pattern in a home and adjust the circulator run time automatically. Hot water will always be available when needed.