18" x 36" or 36" x 18" Cube Core Eggcrate Return Air Grille Compatible with Duct 6" Designed for both wall and

Designed for both wall and ceiling applications

Durable Construction – Made from high-quality

+ Product Details Size – 10" round duct opening-

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

Actual Filter Size – 33 3/4"w x 35 3/4" x 1"

18" x 36" or 36" x 18" Cube Core Eggcrate Return Air Grille Compatible with Duct 6" Designed for both wall and+ Product Details Size 18" x 36" or 36" x 18" is the size for the duct opening measurement only, actual front end outer dimensions are approximately 19. 75" X 37. 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