18" x 28" or 28" x 18" Cube Core Eggcrate Return Air Grille white please note that the total

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

Actual Filter Size – 21 3/4"w x 13 3/4" x 1"

Installation Location – Ceiling

actual front end outer dimensions are approximately 30 5/8" width X 38 5/8" height

actual front end outer dimensions are approximately 24 5/8" width X 8 5/8" height

18" x 28" or 28" x 18" Cube Core Eggcrate Return Air Grille white please note that the total+ 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