26"W X 10"H [Duct Opening] Steel Air Vent Return Grille - HVAC VENT DUCT COVER DIFFUSER - [Outer Dimensions: 27.75"W X 11.75"H] w24h24 + Product Details Size – 4 X 12 Is CRFG2028 Width_14in

+ Product Details Size – 36"w X 24"h is the size for the duct opening measurement only

Experience uniform air distribution in every corner

75" width X 27

+ Product Details Size - 20"w X 20"h is the size for the duct opening measurement only

+ Product Details Size - 28"w X 30"h is the size for the duct opening measurement only

26"W X 10"H [Duct Opening] Steel Air Vent Return Grille HVAC VENT DUCT COVER DIFFUSER [Outer Dimensions: 27.75"W X 11.75"H] w24h24 + Product Details Size – 4 X 12 Is CRFG2028 Width_14in + Product Details Size – 36"w X 24"h is the size for the duct opening measurement only Experience uniform air distribution in every corner