45 In.H-W 13.3 In.L Squ Stl Mtrzd Cntrl Dampr For Nominal Duct Diameter Not Applicable Damper Application Motorized Number of Panels 1 Overall Height 45 in Overall Length 13 1/4 in Rough Opening Shape Square For Duct Shape Square Overall Width 45 in Frame Material Thickness 14 ga Blade Material Galvanized Steel Maximum Air Pressure 4 in wg Overall Diameter 45 in Rough Opening Length 43 in Rough Opening Width 43 in Damper Type Dynamic Maximum Air Velocity 3500 fpm