YORK® HOODED ROOF MOUNT PROP FANS move large volumes of air efficiently, quietly and with low discharge velocities. They combine venturi design with the latest developments in T-hood construction for long trouble-free service under difficult weather or outside vibration conditions. Watertight, overlapping seams and heavy gauge materials insure against leakage. YORK® HOODED ROOF MOUNT PROP FANS are designed for aerodynamic efficiency and employ a choice of two propeller types: high speed, cast aluminum and slow speed, fabricated steel. Available in direct drive and belt drive models, they serve supply, exhaust, reversible, gravity-vent and filtered air applications.