28"W X 6"H [Duct Opening] ALUMINUM RETURN GRILLE - Easy Air Flow - Linear Bar Grilles [Outer Dimensions: 29.875"W X 7.875"H] Blade + Product Details Size – 4 X 12 Is CRFG2028 Width_14in

+ Product Details Size – 8"w X 34"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 12" x 10" or 10" x 12" duct opening (measured at the opening)

Enhanced Filtration: Our filters are 25% thicker than competitors'

actual front end outer dimensions are approximately 10 5/8" width X 36 5/8" height

+ Product Details Perfect Fit & Easy Sizing - Designed for a 28" x 12" OR 12" x 28" duct opening (measured at the opening)

28"W X 6"H [Duct Opening] ALUMINUM RETURN GRILLE Easy Air Flow Linear Bar Grilles [Outer Dimensions: 29.875"W X 7.875"H] Blade + Product Details Size – 4 X 12 Is CRFG2028 Width_14in + Product Details Size – 8"w X 34"h is the size for the duct opening measurement only + Product Details Perfect Fit & Easy Sizing Designed for a 12" x 10" or 10" x 12" duct opening (measured at the opening)