27.8 In.H-W 4.5 In.L Alu Spring Bkdrft Dampr, Damper Application Backdraft, For Nominal Duct Diameter 28 in, Frame Material Galvanized Steel, Number of Panels 1, Maximum Air Velocity 2000 fpm, Overall Height 27 3/4 in, Rough Opening Diameter 28 in,...
27.8 In.H-W 4.5 In.L Alu Spring Bkdrft Dampr, Damper Application Backdraft, For Nominal Duct Diameter 28 in, Frame Material Galvanized Steel, Number of Panels 1, Maximum Air Velocity 2000 fpm, Overall Height 27 3/4 in, Rough Opening Diameter 28 in,...