Broan 353 Gable Mount 120-Volt Powered Attic Ventilator, 1020 CFM 3.4 Amps, 1020 CFM for up to 1,630 square feet of attic space Quiet, high-performance operation for inside-the-attic applications Precision balanced 14 diameter metal blade for maximum air flow  minimum sound level 22 gage galvanized steel housing with ribs for added strength with mounting brackets that simplify installation Operates automatically - adjustable thermostat built-in with thermally protected permanently lubricated motor