Maintenance free, totally enclosed motor with thermally protected pre-lubricated ball bearings. Energy-efficient polypropylene fan blades are rust and corrosion resistant. Heavy molded polyethylene fan housing will not rust or corrode. Heavy-gauge, welded wire front fan guard is polyester coated for corrosion resistance. PVC shutter constructed of white poly materials and assembled with nylon bearings. U.S.A.Fan Diameter (in.) 12 Air Delivery (CFM) 1,604 HP 1/3 Volts 115/230 Dimensions L x W x H (in.) 19 1/2 x 15 1/2 x 15 1/2 Amps 3.8, 1.9 Speed (RPM) 1,725. * Direct drive * Flush mount * Variable speed capable * Rough-in opening: 16 3/4in.H x 15 3/4in.W