18" x 20" or 20" x 18" Cube Core Eggcrate Return Air Grille Aluminum + Product Details Size – 4 X 12 Is CRFG2028 Width_14in

+ Product Details Size – 10" x 16" or 16" x 10" is the size for the duct opening measurement only

actual front end outer dimensions are approximately 20 5/8" width X 34 5/8" height

+ Product Details Size – 8"w X 36"h is the size for the duct opening measurement only

and a polished

Equipped with a locking eight-tumbler key system

18" x 20" or 20" x 18" Cube Core Eggcrate Return Air Grille Aluminum + Product Details Size – 4 X 12 Is CRFG2028 Width_14in + Product Details Size – 10" x 16" or 16" x 10" is the size for the duct opening measurement only actual front end outer dimensions are approximately 20 5 8" width X 34 5 8" height