"The Wallmaster exhaust fan eliminates heat build up in barns, greenhouses and industrial buildings. Constructed with a sturdy 18-g. galvanized steel housing, a 1ft. x 2in. mesh intake guard and an exhaust shutter. U.S.A. Dimensions L x W x H in. 54 x 27 x 54, Air Delivery CFM 20,900, Volts 230/460, Speeds qty. 1, Speed RPM 575, Amps 3.0/1.5, Needs to be Hardwired Yes, Fan Diameter in. 50, HP 1. 3 wing cast aluminum blade Three-phase motor Guard is hot dip galvanized after welding and attached with noise-reducing clip Aluminum shutter has two tie bars to reduce flapping in high wind Maintenance-free motor 54 1/4in. square rough-in"