Round Bypass Zoning Damper Steel 12 in dia For Nominal Duct Diameter 12 in Damper Application Zoning Number of Panels Not Applicable Overall Height 35 1/4 in Overall Length 14 in Rough Opening Shape Round For Duct Shape Round Overall Width 15 1/2 in Frame Material Thickness Not Applicable Blade Material Galvanized Steel Maximum Air Pressure Not Applicable Overall Diameter 12 in Rough Opening Length 12 in Rough Opening Width 12 in Damper Type Dynamic