4"W X 18"H [Duct Opening] Steel Air Vent Return Grille - HVAC VENT DUCT COVER DIFFUSER - [Outer Dimensions: 5.75"W X 19.75"H] 18in diameter + Product Details Size –

+ Product Details Size – 8" x 8" is the size for the duct opening measurement only

'block' : 'none'

+ Product Details Size - 30"w X 14"h is the size for the duct opening measurement only

that will overlap at wall joint

R Value Rating of Insulation - R3

4"W X 18"H [Duct Opening] Steel Air Vent Return Grille - HVAC VENT DUCT COVER DIFFUSER - [Outer Dimensions: 5.75"W X 19.75"H] 18in diameter + Product Details Size –+ Product Details Size 4"w X 18"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 5. 75" width X 19. 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.