28"W X 18"H [Duct Opening] Steel Air Vent Return Grille - HVAC VENT DUCT COVER DIFFUSER - [Outer Dimensions: 29.75"W X 19.75"H] w12h12 this grill will provide the 4 X 12 Is CRFG2028 Width_14in

this grill will provide the design aesthetic you're looking for

+ Product Details Size - 34"w X 10"h is the size for the duct opening measurement only

and Centralized Air Ducted Units

+ Product Details Size - 26"w X 10"h is the size for the duct opening measurement only

+ Product Details Size - 25"w X 10"h is the size for the duct opening measurement only

28"W X 18"H [Duct Opening] Steel Air Vent Return Grille HVAC VENT DUCT COVER DIFFUSER [Outer Dimensions: 29.75"W X 19.75"H] w12h12 this grill will provide the 4 X 12 Is CRFG2028 Width_14in this grill will provide the design aesthetic you're looking for + Product Details Size 34"w X 10"h is the size for the duct opening measurement only