8" x 18" or 18" x 8" Cube Core Eggcrate Return Air Grille 14in diameter + Product Details Size -

+ Product Details Size - 25"w X 6"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 28 5/8" width X 12 5/8" height

and durability

Actual Filter Size – 21 3/4"w x 19 3/4" x 1"

actual front end outer dimensions are 3"

8" x 18" or 18" x 8" Cube Core Eggcrate Return Air Grille 14in diameter + Product Details Size -+ Product Details Size 8" x 18" or 18" x 8" is the size for the duct opening measurement only, actual front end outer dimensions are approximately 9. 75" X 19. 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