28" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Black + Product Details Size - 4 X 12 Is CRFG2028 Width_14in

+ Product Details Size - 20"w X 8"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 34" x 32" Or 32" x 34" duct opening (measured at the opening)

+ Product Details Size - 24"w X 30"h is the size for the duct opening measurement only

+ Product Details Size - 16"w X 20"h is the size for the duct opening measurement only

+ Product Details Size – 18" x 32" or 32" x 18" is the size for the duct opening measurement only

28" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Black + Product Details Size 4 X 12 Is CRFG2028 Width_14in + Product Details Size 20"w X 8"h is the size for the duct opening measurement only + Product Details Perfect Fit & Easy Sizing Designed for a 34" x 32" Or 32" x 34" duct opening (measured at the opening)