12" x 20" or 20" x 12" Cube Core Eggcrate Return Air Grille 18" Diameter It has an outer surface

It has an outer surface made of high-quality aluminum foil and an inner surface made of metalized PET with inside high-tensile spring steel wire

actual front end outer dimensions are approximately 27

Great emphasis has been invested in the design of this product to prevent it from kinking in sharp bends & turns and to hold steady and at full diameter in all applications

actual front end outer dimensions are approximately 12 5/8" width X 26 5/8" height

75"H – fits a 30" X 6" duct opening

12" x 20" or 20" x 12" Cube Core Eggcrate Return Air Grille 18" Diameter It has an outer surface+ Product Details Size 12" x 20" or 20" x 12" is the size for the duct opening measurement only, actual front end outer dimensions are approximately 13. 75" X 21. 75". High Quality High quality, rust free aluminum construction with smooth finished edges and counter sunk screw holes (screws included); no sharp edges.. Installation Location sidewall and ceiling. Design Cubic core eggcrate design Offers highest airflow efficiency at almost 95%, reducing