MRCOOL MCAEHFD5X1AA Signature Series Multi-Position Air Handler Heat Kit 5kW is an electric heating accessory designed to provide supplemental or emergency heat for compatible air handler systems. It works by converting electrical energy into heat through integrated heating elements, delivering warm airflow when additional heating is required. https://www.partshnc.com/mrcool-signature-series-5kw-heat-kit-mcaehfd5x1aa