18.5 Inch Fan Shutter - Durable Metal Window Cover for Home & Office Ventilation | Perfect for Airflow Control, Privacy & Security

Backdraft Damper / Wall Shutter, Fits Fan Dia. 18 in, Shutter Overall Size 21 in x 21 in, Shutter Construction Material G-90 Galvanized Steel Frame and Tie Rods, Shutter Opening Required 18-1/2 in x 18-1/2 in, Shutter Free Area 2.043 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 Mill Finish Aluminum