63 In.H-W 12.8 In.L Squ Stl Mtrzd Cntrl Dampr, For Nominal Duct Diameter Not Applicable, Damper Application Motorized, Number of Panels 2, Overall Height 63 in, Overall Length 12 3/4 in, Rough Opening Shape Square, For Duct Shape Square, Overall Width 63 in, Frame Material Thickness 14 ga, Blade Material Galvanized Steel, Maximum Air Pressure 4 in wg, Overall Diameter 63 in, Rough Opening Length 61 in, Rough Opening Width 61 in, Damper Type Dynamic, Maximum Air Velocity 3500 fpm