6" x 18" or 18" x 6" Cube Core Eggcrate Return Air Grille 8" Diameter Universal Fit – Measures 3-7/8"

Universal Fit – Measures 3-7/8" wide x 3-1/2" high x 3" deep

actual front end outer dimensions are approximately 12 5/8" width X 8 5/8" height

Tough reinforced metallized polyester jacket - tear and puncture resistant

actual front end outer dimensions are approximately 16 5/8" width X 28 5/8" height

6" x 18" or 18" x 6" Cube Core Eggcrate Return Air Grille 8" Diameter Universal Fit – Measures 3-7/8"+ Product Details Size 6" x 18" or 18" x 6" is the size for the duct opening measurement only, actual front end outer dimensions are approximately 7. 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