6" x 28" or 28" x 6" Cube Core Eggcrate Return Air Grille Curved Blade Steel Ideal for Walls & Ceilings:

Ideal for Walls & Ceilings: Designed for seamless installation in standard 16" X 6" duct openings

+ Product Details Size – 12" x 36" or 36" x 12" is the size for the duct opening measurement only

Actual Filter Size – 7 3/4"w x 23 3/4" x 1"

Measure the size of the air duct/drywall opening

6" x 28" or 28" x 6" Cube Core Eggcrate Return Air Grille Curved Blade Steel Ideal for Walls & Ceilings:+ Product Details Size 6" x 28" or 28" x 6" is the size for the duct opening measurement only, actual front end outer dimensions are approximately 7. 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