48 in Backdraft Damper / Wall Shutter, 48-1/2 in x 48-1/2 in, DAYTON, Mfr# 1C211

51 In.H-W 5.75 In.L Alu Wall Vent Shutter, Damper Application Backdraft, For Nominal Duct Diameter Not Applicable, Frame Material Galvanized Steel, Number of Panels 2, Maximum Air Velocity 2500 fpm, Overall Height 51 in, Rough Opening Diameter 48 1/2 in, Rough Opening Shape Square, Fits Fan Diameter 48 in, For Duct Shape Not Applicable, Free Area 12.9 sq ft, Overall Width 51 in, Frame Material Thickness 20 ga, Overall Length 5 3/4 in, Connection Type Not Applicable, Frame Depth 2 1/2 in