36" x 22" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w28h28 + Product Details Size - 4 X 12 Is CRFG2028 Width_14in

+ Product Details Size - 14"w X 24"h is the size for the duct opening measurement only

+ Product Details Size – 12"w X 8"h is the size for the duct opening measurement only

+ Product Details Size - 28"w X 18"h is the size for the duct opening measurement only

efficient airflow

+ Product Details Size - 30"w X 36"h is the size for the duct opening measurement only

36" x 22" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w28h28 + Product Details Size 4 X 12 Is CRFG2028 Width_14in + Product Details Size 14"w X 24"h is the size for the duct opening measurement only + Product Details Size – 12"w X 8"h is the size for the duct opening measurement only