20" x 36" or 36" x 20" Cube Core Eggcrate Return Air Grille Insulated Line Set + Product Details Size –

+ Product Details Size – 34"w X 26"h is the size for the duct opening measurement only

Ideal for Walls & Ceilings: Designed for seamless installation in standard 16" X 10" duct openings

+ Product Details Size - 22"w X 14"h is the size for the duct opening measurement only

75"H – fits a 18" X 4" duct opening

Actual Filter Size – 31 3/4"w x 15 3/4" x 1"

20" x 36" or 36" x 20" Cube Core Eggcrate Return Air Grille Insulated Line Set + Product Details Size –+ Product Details Size 20" x 36" or 36" x 20" is the size for the duct opening measurement only, actual front end outer dimensions are approximately 21. 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