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 12 5/8" width X 26 5/8" height

+ Product Details Size – 8"w X 28"h is the size for the duct opening measurement only

75"H – fits a 30" X 6" duct opening

+ Product Details Size – 24"w X 24"h is the drop ceiling HVAC supply grille size - for T-Bar lay-in

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