12" x 20" or 20" x 12" Cube Core Eggcrate Return Air Grille 18" Diameter Actual Filter Size – 17

Actual Filter Size – 17 3/4"w x 27 3/4" x 1"

875" width X 15

+ Product Details Size – 24" x 24" is the size for the duct opening measurement only

our damper is designed to perfectly align with your setup

Don’t worry

12" x 20" or 20" x 12" Cube Core Eggcrate Return Air Grille 18" Diameter Actual Filter Size – 17+ Product Details Size 12" x 20" or 20" x 12" is the size for the duct opening measurement only, actual front end outer dimensions are approximately 13. 75" X 21. 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