Round Bypass Zoning Damper Steel 8 in dia For Nominal Duct Diameter 8 in Damper Application Zoning Number of Panels Not Applicable Overall Height 9 5/8 in Overall Length 11 1/2 in Rough Opening Shape Round For Duct Shape Round Overall Width 8 in Frame Material Thickness Not Applicable Blade Material Galvanized Steel Maximum Air Pressure Not Applicable Overall Diameter 8 in Rough Opening Length 8 in Rough Opening Width 8 in Damper Type Dynamic Maximum Air Velocity Not Applicable