12" x 18" or 18" x 12" Cube Core Eggcrate Return Air Grille ceiling Ideal for Walls & Ceilings:

Ideal for Walls & Ceilings: Designed for seamless installation in standard 10" X 6" duct openings

+ Product Details Size – 26"w X 26"h is the size for the duct opening measurement only

Easy Installation – Just pop the diffuser right into the wall duct hole and the side springs will hold it right into place so that it looks clean

actual front end outer dimensions are approximately 18 5/8" width X 30 5/8" height

12" x 18" or 18" x 12" Cube Core Eggcrate Return Air Grille ceiling Ideal for Walls & Ceilings:+ Product Details Size 12" x 18" or 18" x 12" is the size for the duct opening measurement only, actual front end outer dimensions are approximately 13. 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