16" x 18" or 18" x 16" Cube Core Eggcrate Return Air Grille Aluminum Bar + Product Details Size –

+ Product Details Size – 40"w X 10"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 12" x 12" duct opening (measured at the opening)

180 Degrees Double Direction Adjustable - Fins Are Manually Adjustable Individually for Optimal Air Distribution

with actual outer dimensions of 34

16" x 18" or 18" x 16" Cube Core Eggcrate Return Air Grille Aluminum Bar + Product Details Size –+ Product Details Size 16" x 18" or 18" x 16" is the size for the duct opening measurement only, actual front end outer dimensions are approximately 17. 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