40"W X 6"H [Duct Opening] Steel Air Vent Return Grille - HVAC VENT DUCT COVER DIFFUSER - [Outer Dimensions: 41.75"W X 7.75"H] w8h8 R value rating of insulation

R value rating of insulation - r3

and the second number represents the height

+ Product Details Size – 4"w X 12"h is the size for the duct opening measurement only

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40"W X 6"H [Duct Opening] Steel Air Vent Return Grille - HVAC VENT DUCT COVER DIFFUSER - [Outer Dimensions: 41.75"W X 7.75"H] w8h8 R value rating of insulation+ Product Details Size 40"w X 6"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 41. 75" width X 7. 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.