DAYTON 5NKN4 Damper,Backdraft,Wall Mount,19-3/4 In Sq
19.75 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 19 3/4 in, Rough Opening Diameter 17...