Exhaust Fan Assembled Unassembled Blade Diameter 42 in Blade Material Steel Frame Material Steel For Maximum Motor Horsepower 1 1/2 hp For Maximum Motor Speed 608 RPM For Minimum Motor Horsepower 1/3 hp For Minimum Motor Speed 366 RPM Maximum Airflow 20 998 cfm Maximum Static Pressure 0.75 in wg Minimum Airflow 12 640 cfm For Cut-Out Height 44 1/2 in For Cut-Out Width 44 1/2 in For Cut-Out Diameter 44 1/2 in Guard Type None Method of Construction Stamped Number of Blades 6