10" x 28" or 28" x 10" Cube Core Eggcrate Return Air Grille 10in diameter 75" width X 33

75" width X 33

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

75" width X 37

and smooth surface

10" x 28" or 28" x 10" Cube Core Eggcrate Return Air Grille 10in diameter 75" width X 33+ Product Details Size 10" x 28" or 28" x 10" is the size for the duct opening measurement only, actual front end outer dimensions are approximately 11. 75" X 29. 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