MRCOOL HHK-10 ProDirect Series Top-Discharge Heat Kit is an electric heating accessory designed to provide supplemental or emergency heat for compatible HVAC systems. It works by using electric resistance heating elements to generate warm air, which is distributed through the air handler and ductwork to maintain comfortable indoor temperatures during colder weather. https://www.partshnc.com/mrcool-prodirect-top-discharge-heat-kit-hhk-10