12.75 In.H-W 4.5 In.L Aluminum Backdraft Dampr Damper Application Backdraft For Nominal Duct Diameter Not Applicable Frame Material Aluminum Number of Panels 1 Maximum Air Velocity 2250 fpm Overall Height 12 3/4 in Rough Opening Diameter Not Applicable Rough Opening Shape Square Fits Fan Diameter 10 in For Duct Shape Square Free Area 0.4 sq ft Overall Width 12 3/4 in Frame Material Thickness 0.1 in Overall Length 4 1/2 in Connection Type Not Applicable Frame Depth 1 5/8 in