18" x 28" or 28" x 18" Cube Core Eggcrate Return Air Grille white + Product Details Size –

+ Product Details Size – 16"w X 20"h is the size for the duct opening measurement only

and sound level range of NC 25 to 35

+ Product Details Perfect Fit & Easy Sizing - Designed for a 14" x 24" OR 24" X 14" duct opening (measured at the opening)

actual front end outer dimensions are approximately 10 5/8" width X 16 5/8" height

please note that the total outer dimensions of the grille measure 7" in diameter

18" x 28" or 28" x 18" Cube Core Eggcrate Return Air Grille white + Product Details Size –+ Product Details Size 18" x 28" or 28" x 18" is the size for the duct opening measurement only, actual front end outer dimensions are approximately 19. 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