28" x 30" or 30" x 28" Cube Core Eggcrate Return Air Grille Aluminum Adjustable Curved Blade + Product Details Size -

+ Product Details Size - 26"w X 8"h is the size for the duct opening measurement only

75" Width X 37

Actual Filter Size – 15 3/4"w x 17 3/4" x 1"

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

75"H – fits a 16" X 8" duct opening

28" x 30" or 30" x 28" Cube Core Eggcrate Return Air Grille Aluminum Adjustable Curved Blade + Product Details Size -+ Product Details Size 28" x 30 or 30" x 28" is the size for the duct opening measurement only, actual front end outer dimensions are approximately 29. 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