20"W X 4"H [Duct Opening] Steel Air Vent Return Grille - HVAC VENT DUCT COVER DIFFUSER - [Outer Dimensions: 21.75"W X 5.75"H] Color_R-4.2 Yellow + Product Details Size -

+ Product Details Size - 36"w X 18"h is the size for the duct opening measurement only

+ Product Details Size – 10" X 2" is the size for the duct opening (floor/vent hole) measurement only

they seamlessly integrate into your space

Insulation – A thick blanket of fiberglass insulation provides you with an R-Value of 8

20"W X 4"H [Duct Opening] Steel Air Vent Return Grille - HVAC VENT DUCT COVER DIFFUSER - [Outer Dimensions: 21.75"W X 5.75"H] Color_R-4.2 Yellow + Product Details Size -+ Product Details Size 20"w X 4"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 21. 75" width X 5. 75" height. Design Easy unrestricted airflow for your HVAC system 50 angled to provide maximum airflow. High Quality Solid stamped steel with counter sunk screw holes (screws included) and no sharp edges. Powder Coat Finish Smooth, shiny, scratch resistant, beautiful. Looks like it was just waxed.