Shutter Mount Exhaust Fan Assembled Assembled Blade Diameter 18 in Blade Material Steel Control Type Rotary Dial Drive Type Direct Drive Duct Diameter Not Applicable Exhaust Airflow @ 0.000 in SP 3 150 cfm For Cut-Out Height 20 in For Cut-Out Width 20 in For Maximum Wall Thickness 5 in For Minimum Wall Thickness 5 in Frame Material Aluminum Guard Finish Chrome Guard Material Steel Guard Type Intake Housing Material Aluminum Housing Finish Aluminum Includes Shutter