12" x 20" or 20" x 12" Cube Core Eggcrate Return Air Grille 18" Diameter + Product Details Size –

+ Product Details Size – 24" x 24" is the size for the duct opening measurement only

+ Product Details Size - 20"w X 12"h is the size for the duct opening measurement only

875" width X 15

+ Product Details Size - 34"w X 8"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 12 5/8" width X 24 5/8" height

12" x 20" or 20" x 12" Cube Core Eggcrate Return Air Grille 18" Diameter + Product Details Size –+ 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