Exhaust/Supply Fan, Assembled Assembled, Blade Diameter 20 in, Blade Material Aluminum, Drive Type Direct Drive, Duct Diameter 20 1/2 in, Exhaust Airflow @ 0.000 in SP 3,859 cfm, Frame Finish Galvanized, Frame Material Steel, Guard Type None, Includes Reversing Switch, Includes Dehumidistat No, Maximum Noise Level 0.84 sones