12 In.dia GSteel Manual Balancing Dampr Damper Application Balancing For Nominal Duct Diameter 12 in Frame Material Steel Number of Panels 1 Maximum Air Velocity 2000 fpm Overall Height Not Applicable Rough Opening Diameter 12 in Rough Opening Shape Round Fits Fan Diameter Not Applicable For Duct Shape Round Overall Width Not Applicable Frame Material Thickness 16 ga Overall Length 6 3/8 in Connection Type Not Applicable Frame Depth 6 3/8 in Rough Opening Length Not Applicable