51 In.H-W 13.3 In.L Squ Alu Mtrzd Cntrl Dampr For Nominal Duct Diameter Not Applicable Damper Application Motorized Number of Panels 1 Overall Height 51 in Overall Length 13 1/4 in Rough Opening Shape Square For Duct Shape Square Overall Width 51 in Frame Material Thickness 0.1 in Blade Material Aluminum Maximum Air Pressure 4 in wg Overall Diameter 51 in Rough Opening Length 49 in Rough Opening Width 49 in Damper Type Dynamic Maximum Air Velocity 3500 fpm