30" x 30" Cube Core Eggcrate Return Air Grille steel + Product Details Size -

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

+ Product Details Size – 6" x 16" or 16" x 6" is the size for the duct opening measurement only

Ideal for Walls & Ceilings: Designed for seamless installation in standard 16" X 16" duct openings

+ Product Details Size – 10" x 12" or 12" x 10" is the size for the duct opening measurement only

30" x 30" Cube Core Eggcrate Return Air Grille steel + Product Details Size -+ Product Details Size 30" x 30" is the size for the duct opening measurement only, actual front end outer dimensions are approximately 31. 75" X 31. 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 electric