54" double panel front flange exhaust shutter; fits 54" fan diameter, Overall Size: 57" x 57", Shutter Construction Material: extruded aluminum frame and galvanized tie rods, Shutter Opening Required: 54-1/2" x 54-1/2", Shutter Free Area: 17.007 sq ft, Shutter Mounting Position: vertical, Shutter Mounting Location: wall, Frame Depth: 2-1/2", Open Depth: 5-3/4", Flange Width: 1-1/2", pre-punched mounting holes, Number of Panels: 2, Maximum Velocity: 2500 FPM, Blade Material: mill-finish aluminum, for use with vertical-mounted exhaust fans, Weight: 38 lbs, Origin: USA