11.8 In.H-W 12 In.L Spring Fire Dampr w/Sleeve Damper Application Fire Frame Material Galvanized Steel Number of Panels 1 Maximum Air Velocity 4000 fpm Overall Height 11 3/4 in Rough Opening Diameter Not Applicable Rough Opening Shape Square Fits Fan Diameter Not Applicable For Duct Shape Square Free Area 0.6 sq ft Overall Width 11 3/4 in Frame Material Thickness 22 ga Overall Length 12 in Connection Type Not Applicable Frame Depth 12 in Rough Opening Length Not Applicable