MRCOOL MLP1SH High Altitude Single Stage Gas Furnace Propane Conversion Kit is an accessory designed to adapt compatible MRCOOL gas furnaces for propane operation at higher elevations. It works by modifying the furnace’s fuel delivery components to provide the proper propane flow and combustion characteristics required for safe, efficient operation in reduced-air-density environments. https://www.partshnc.com/mrcool-high-altitude-propane-conversion-kit-mlp1sh