8" x 36" or 36" x 8" Cube Core Eggcrate Return Air Grille Grilles + Product Details Size –

+ Product Details Size – 18"w X 28"h is the size for the duct opening measurement only

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

actual front end outer dimensions are approximately 30 5/8" width X 32 5/8" height

+ Product Details Size - 4"w X 32"h is the size for the duct opening measurement only

8" x 36" or 36" x 8" Cube Core Eggcrate Return Air Grille Grilles + Product Details Size –+ Product Details Size 8" x 36" or 36" x 8" is the size for the duct opening measurement only, actual front end outer dimensions are approximately 9. 75" X 37. 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