More air volume with fewer fans - 29,700 CFM at 0.05 inches static pressure in recent independent wind tunnel tests.
More consistent air flow - OFS Doors don't suffer the 12-15% loss of efficiency and air speed typical of dirty louver-style shutters.
Compressible, one-piece cone for 60-inch-on-center (152.4-cm) installation.
Sturdy, corrosion-resistant fiberglass housing with cast aluminum blade and corrosion-resistant components.
Heavy-duty, cast iron, air-handler type bearings are self-aligning, pre-lubricated, and include a zerk fitting, as well as being shielded from moisture and dust.
Pre-assembled including doors, with a true flush mount.
Just two moving parts for greater reliability and easier cleaning.
OFS generous extended warranty including limited lifetime coverage for housing and blade, and a bonus year on motors.