Zone Control Damper For Nominal Duct Diameter 8 in Damper Application Motorized Number of Panels Not Applicable Overall Height 12 3/4 in Overall Length 11 in Rough Opening Shape Round For Duct Shape Round Overall Width 10 3/4 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