Backdraft Damper / Wall Shutter Fits Fan Dia 16 in Shutter Overall Size 19 in x 19 in Shutter Construction Material Extruded Aluminum Frame and G-90 Galvanized Tie Rods Shutter Opening Required 16-1/2 in x 16-1/2 in Shutter Free Area 1.436 sq ft Vertical Shutter Mounting Position Shutter Mounting Location Wall Frame Depth 2 1/2 in Open Depth 5 3/4 in Flange Width 1 1/2 in Mounting Hole Size Prepunched Max Velocity 2500 FPM Blade Material White Painted Aluminum