Shutter Mount Exhaust Fan, Assembled Assembled, Blade Diameter 20 in, Blade Material Aluminum, Control Type Pull Chain, Drive Type Direct Drive, Duct Diameter 20 3/8 in, Exhaust Airflow @ 0.000 in SP 2,235 cfm, For -Out Height 20 1/2 in, For -Out Width 20 1/2 in, For Maximum Wall Thickness 5 1/2 in, For Minimum Wall Thickness 3 in, Frame Material Aluminum, Guard Finish Chrome, Guard Material Steel, Guard Type Exhaust, Housing Material Aluminum, Steel, Housing Finish Galvanized