10"W X 16"H [Duct Opening] Steel Air Vent Return Grille - HVAC VENT DUCT COVER DIFFUSER - [Outer Dimensions: 11.75"W X 17.75"H] w20h20 + Product Details Size - 4 X 12 Is CRFG2028 Width_14in

+ Product Details Size - 18"w X 16"h is the size for the duct opening measurement only

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+ Product Details Size – 12" x 24" or 24" x 12" is the size for the duct opening measurement only

+ Product Details Size - 30"w X 12"h is the size for the duct opening measurement only

Measure the size of the air duct/drywall opening

10"W X 16"H [Duct Opening] Steel Air Vent Return Grille HVAC VENT DUCT COVER DIFFUSER [Outer Dimensions: 11.75"W X 17.75"H] w20h20 + Product Details Size 4 X 12 Is CRFG2028 Width_14in + Product Details Size 18"w X 16"h is the size for the duct opening measurement only } function toggleAccordion(event) { event