36 in Backdraft Damper / Intake Shutter, 37 in x 37 in, DAYTON, Mfr# 4YN18

38.75 In.H-W 4.5 In.L Alu Intake Shutter Dampr, For Nominal Duct Diameter Not Applicable, Frame Material Aluminum, Number of Panels 1, Maximum Air Velocity 2250 fpm, Overall Height 38 3/4 in, Rough Opening Diameter 37 in, Rough Opening Shape Square, Fits Fan Diameter 36 in, For Duct Shape Not Applicable, Free Area 6.6 sq ft, Overall Width 38 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, Rough Opening Length 37 in