Standard sizes are 24 in. thru 60 in. blade diameter CFM ranges from 5,400 to 57,483 Motors are heavy duty totally enclosed fan cooled Designed for Intake, Exhaust or Reversible Systems Taper lock bushing between propeller and shaft for ease of removal Four and Six high efficient Air Foil cast aluminum blades Welded steel structural frame for added support with less vibration Deep spun venturi-type orifice for quieter, more efficient operation Polyester powder coated inside panel for long life and superior corrosion resistance