28"W X 6"H [Duct Opening] Steel Air Vent Return Grille - HVAC VENT DUCT COVER DIFFUSER - [Outer Dimensions: 29.75"W X 7.75"H] Ceiling + Product Details Size - 4 X 12 Is CRFG2028 Width_14in

+ Product Details Size - 8"w X 26"h is the size for the duct opening measurement only

you have 16 different varieties to choose from

of up to 300m3/h

+ Product Details Size - 25"w X 8"h is the size for the duct opening measurement only

+ Product Details Size - 25"w X 6"h is the size for the duct opening measurement only

28"W X 6"H [Duct Opening] Steel Air Vent Return Grille HVAC VENT DUCT COVER DIFFUSER [Outer Dimensions: 29.75"W X 7.75"H] Ceiling + Product Details Size 4 X 12 Is CRFG2028 Width_14in + Product Details Size 8"w X 26"h is the size for the duct opening measurement only you have 16 different varieties to choose from