18" x 28" or 28" x 18" Cube Core Eggcrate Return Air Grille white actual front end outer dimensions

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

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

Installation Location – Ceiling

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

Design – Removable door/face for easy filter change & cleaning - uses a 1" thick filter

18" x 28" or 28" x 18" Cube Core Eggcrate Return Air Grille white actual front end outer dimensions+ 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