Backdraft Damper / Wall Shutter, Fits Fan Dia. 36 in, Shutter Overall Size 42 in x 42 in, Shutter Construction Material Extruded Aluminum Frame and G-90 Galvanized Tie Rods, Shutter Opening Required 39-1/2 in x 39-1/2 in, Shutter Free Area 8.995 sq ft, Vertical Shutter Mounting Position, Shutter Mounting Location Wall, Length 42 in, Width 42 in, Frame Depth 2 1/2 in, Open Depth 5 3/4 in, Flange Width 1 1/2 in, Mounting Hole Size 9/64 in, Max. Velocity 2500 FPM. This item has been restricted from sale in the following state (s): []