Exhaust Fan Control Type Rotary Dial Duct Diameter Not Applicable Exhaust Airflow @ 0.000 in SP 180 cfm For Maximum Wall Thickness 5 1/2 in For Minimum Wall Thickness 3 in Housing Material Steel Housing Finish Galvanized Includes Adjustable Speed Switch Maximum Airflow 180 cfm Maximum Coverage Area 140 sq ft Maximum Noise Level 5 sones