20" x 28" or 28" x 20" Cube Core Eggcrate Return Air Grille 10in diameter + Product Details Size –

+ Product Details Size – 12"w X 18"h is the size for the duct opening measurement only

Crafted from robust 20-gauge steel

Heavy-gauge all-steel construction

Actual Filter Size – 11 3/4"w x 25 3/4" x 1"

Ideal for Walls & Ceilings: Designed for seamless installation in standard 14" X 6" duct openings

20" x 28" or 28" x 20" Cube Core Eggcrate Return Air Grille 10in diameter + Product Details Size –+ Product Details Size 20" x 28" or 28" x 20" is the size for the duct opening measurement only, actual front end outer dimensions are approximately 21. 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