20" x 16" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Color_Red Oak Wood + Product Details Size – 4 X 12 Is CRFG2028 Width_14in

+ Product Details Size – 26" x 30" or 30" x 26" is the size for the duct opening measurement only

+ Product Details Size – 8" x 20" or 20" x 8" is the size for the duct opening measurement only

Actual Filter Size – 23 3/4"w x 15 3/4" x 1"

+ Product Details Size – 8" x 12" or 12" x 8" is the size for the duct opening measurement only

actual front end outer dimensions are 9

20" x 16" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Color_Red Oak Wood + Product Details Size – 4 X 12 Is CRFG2028 Width_14in + Product Details Size – 26" x 30" or 30" x 26" is the size for the duct opening measurement only + Product Details Size – 8" x 20" or 20" x 8" is the size for the duct opening measurement only