MRCOOL MDPHK-15 DC Inverter Packaged Unit Heat Kit 15kW is an electric heating accessory designed to provide supplemental or emergency heat for compatible DC inverter packaged HVAC units. It works by converting electrical energy into heat through integrated heating elements, delivering reliable warm airflow when additional heating capacity is needed. https://www.partshnc.com/mrcool-dc-inverter-packaged-unit-15kw-heat-kit-mdphk-15