Truaire C160MWP 04X12(Duct Opening Measurements) Decorative Floor Grille 4-Inch by 12-Inch Plastic Floor Diffuser, Composite Collection, White Finish Rust proof ABS resin Model Size Indicates Duct Opening Measurements not Wall Opening Measurements. Dishwasher safe Great for high humidity area The actual face size is 13.5-inch in width and 5.5-inch in height.