Truaire C168-ODF 04X12(Duct Opening Measurements) Solid Oak Floor Grille 4-Inch by 12-Inch Solid Oak Floor Diffuser, Dark Oak Finish Smoothglide damper Model Size Indicates Duct Opening Measurements not Wall Opening Measurements. High quality steel components , no plastic Premium stain and lacquer finish The actual face size is 13.5-inch in width and 5.5-inch in height.