Truaire C210VM 10X04(Duct Opening Measurements) Bar Type Supply Diffuser 10-Inch by 4-Inch Sidewall or Ceiling Air Supply Grille, White Smoothglide damper Model Size Indicates Duct Opening Measurements not Wall Opening Measurements. High quality steel components , no plastic High quality powder coated The actual face size is 11.75-inch in width and 5.75-inch in height.