10" x 18" or 18" x 10" Cube Core Eggcrate Return Air Grille Grilles + Product Details Size –

+ Product Details Size – 28"w X 6"h is the size for the duct opening measurement only

Actual Filter Size – 13 3/4"w x 15 3/4" x 1"

+ Product Details Size – 6" x 14" or 14" x 6" is the size for the duct opening measurement only

during winter

+ Product Details Size – 10"w X 16"h is the size for the duct opening measurement only

10" x 18" or 18" x 10" Cube Core Eggcrate Return Air Grille Grilles + Product Details Size –+ Product Details Size 10" x 18" or 18" x 10" is the size for the duct opening measurement only, actual front end outer dimensions are approximately 11. 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