CAN BE USED WITH HEAT EXCHANGERS ROOF TOP AIR CONDITIONERS COMMERCIAL AND INDUSTRIAL EQUIPMENT WALK-IN REFRIGERATION UNITS AND GENERAL COOLING/HEATING APPLICATIONS. BLADES ARE MADE OF HIGH STRENGTH ALUMINUM. EACH BLADE IS CLEARLY LABELED AS TO PITCH DIAMETER ROTATION AND MAXIMUM RPM. SQUARE PRESSURE-TYPE BLADES ARE REQUIRED FOR MOST CONDENSER APPLICATIONS. INTERCHANGEABLE HUBS MAY BE ATTACHED ON EITHER INTAKE OR DISCHARGE SIDE.