Machine Adapter For Nominal Duct Diameter 20 in Inlet Diameter 20 in Material Stainless Steel Product Type Machine Adapter Material Thickness 20 ga Overall Length 5 1/2 in Maximum Pressure Rating 42 in wc Weight 3.9 lb For Duct Height 20 in Flange Inner Diameter Not Applicable For Duct Width 20 in Flange Outer Diameter Not Applicable Maximum Airflow 15 270 cfm Inside Diameter 19 7/8 in Number of Holes on Flange Not Applicable Overall Width 20 in