12" x 36" or 36" x 12" Cube Core Eggcrate Return Air Grille ceiling actual front end outer dimensions

actual front end outer dimensions are approximately 20 5/8" width X 8 5/8" height

+ Product Details Size - 20"w X 12"h is the size for the duct opening measurement only

Actual Filter Size – 27 3/4"w x 33 3/4" x 1"

+ Product Details Size - 30"w X 20"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 30 5/8" width X 10 5/8" height

12" x 36" or 36" x 12" Cube Core Eggcrate Return Air Grille ceiling actual front end outer dimensions+ Product Details Size 12" x 36" or 36" x 12" is the size for the duct opening measurement only, actual front end outer dimensions are approximately 13. 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