Backdraft Damper, Roof Mount, Exhaust, Damper Size (In.) 9-1/2 x 9-1/2, Overall Size (In.) 11-1/2 x 11-1/2, Flange Width (In.) 1 in, Max. Velocity (FPM) 2,000, Construction Material Aluminum Blades, G-90 Galvanized Steel Frame, Nylon Bushings and Galvanized Steel Tie Rods., Stainless Steel Pivot Pins, Use w/Dayton Ventilators -, Includes Pre-punched Conduit Hole Knock-out and Felted Edges For Quiet Operation