Lorenized powder paint finish on all uncoated steel parts - Triton steel propeller - Steel Venturi/curb cap - Heavy gauge steel lower drum - Steel windband - Heavy duty steel power assembly - 2 point lifting lugs - Butterfly damper doors (24-36 alum, 42-72 galv. steel) - Welded curb cap corners - Adjustable pitch drives through 5 HP motor - Regreasable bearings in a cast housing - Propellers are statically and dynamically balanced - Turned, ground and polished steel shafting - Shaft and bearings protected from the airstream - Motor mounted outside of housing under steel weather cover - Extended lube lines on bearings - Corrosion resistant fasteners - Static resistant belts - All fans factory adjusted to specified RPM.