Backdraft Exhaust Damper, No Flange, Horizontal Mount, Damper Size (In.) 59-3/4 X 59-3/4, Overall Size (In.) 59-3/4 X 59-3/4, Max. Velocity (FPM) 2000, Construction Material G-90 Galvanized Steel Frame and Aluminum Blades, Includes Pre-punched Conduit Hole Knock-out and Felted Edges For Quiet Operation