HEAVY DUTY FOUR WING GALVANIZED STEEL PROPS ARE DESIGNED FOR USE IN INDUSTRIAL AIR CIRCULATORS EXHAUST FAN UNITS AIR COOLED CONDENSING UNITS SMALL COOLING TOWERS AGRICULTURAL VENTILATION EQUIPMENT LARGE UNIT HEATERS COMMERCIAL AND INDUSTRIAL EQUIPMENT ROOF TOP AIR CONDITIONERS GENERAL COOLING AND HEATING APPLICATIONS. L TYPE BUSHING NEEDED.