18" x 34" or 34" x 18" Cube Core Eggcrate Return Air Grille 6" Diameter + Product Details Size –

+ Product Details Size – 28"w X 8"h is the size for the duct opening measurement only

Actual Filter Size – 19 3/4"w x 11 3/4" x 1"

+ Product Details Size – 22"w X 16"h is the size for the duct opening measurement only

thanks to counter-sunk screw holes and included screws

18" x 34" or 34" x 18" Cube Core Eggcrate Return Air Grille 6" Diameter + Product Details Size –+ Product Details Size 18" x 34" or 34" x 18" is the size for the duct opening measurement only, actual front end outer dimensions are approximately 19. 75" X 35. 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