The MRCOOL PHK20H ProDirect Series Heat Kit is an electric heating accessory designed for use with compatible MRCOOL ProDirect air handlers and HVAC systems. It works by generating supplemental electric heat that is distributed through the air handler and ductwork when additional heating is needed. Commonly used as auxiliary or emergency heat, the kit helps maintain indoor comfort dur... https://www.partshnc.com/mrcool-prodirect-series-20kw-heat-kit-phk20h