Exhaust 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 4 558 cfm Frame Finish Galvanized Frame Material Steel Guard Finish Zinc Plated Guard Material Steel Guard Type Intake Includes Dehumidistat No Maximum Noise Level 22 sones