The MRCOOL MDPHK-15 DC Inverter Packaged Unit Heat Kit is a supplemental electric heating accessory designed to provide additional heating capacity for compatible DC inverter packaged HVAC units. It works by using electric resistance heating elements to generate heat, which the packaged unit blower distributes throughout the conditioned space. Designed for use with compatible MRCOOL p... https://www.partshnc.com/mrcool-dc-inverter-packaged-unit-15kw-heat-kit-mdphk-15