The WF50 and WF54 Aerotech fans use high quality components and precise engineering to create a simple, high quality fan with optimal performance at the best price. The cast aluminum drive assembly utilizes enclosed automotive style bearing and comes with a 7 year limited warranty. This feature along with the automotive style belt tensioner and heavy duty galvanized steel propeller promotes top performance. The MONO-STRUT offers strength and durability in a simple design. Now available with the Patent Pending Dragonfly Damper Doors.