Agricultural Wall Exhaust Shutter, Fits Fan Dia. 48 in, Shutter Overall Size 54 in x 54 in, Shutter Construction Material Aluminum Frame and Tie Rods, Shutter Opening Required 51-1/2 in x 51-1/2 in, Shutter Free Area 14.841 sq ft, Vertical Shutter Mounting Position, Shutter Mounting Location Wall, Frame Depth 2 1/4 in, Open Depth 5 3/8 in, Flange Width 1 1/2 in, Mounting Hole Size Prepunched, Max. Velocity 2500 FPM, Blade Material Mill Finish Aluminum, For Use With Agricultural Exhaust Fans