30 in Backdraft Damper / Wall Shutter, 30-1/2 in x 30-1/2 in, DAYTON, Mfr# 3C309

33 In.H-W 5.75 In.L Aluminum Backdraft Damper, Damper Application Backdraft, For Nominal Duct Diameter Not Applicable, Frame Material Aluminum, Number of Panels 1, Maximum Air Velocity 2500 fpm, Overall Height 33 in, Rough Opening Diameter 30 1/2 in, Rough Opening Shape Square, Fits Fan Diameter 30 in, For Duct Shape Not Applicable, Free Area 5.5 sq ft, Overall Width 33 in, Frame Material Thickness 0.8 in, Overall Length 5 3/4 in, Connection Type Not Applicable, Frame Depth 3 in