18" x 24" or 24" x 18" Cube Core Eggcrate Return Air Grille Color_R-4.2 Yellow + Product Details Size –

+ Product Details Size – 18" x 26" or 26" x 18" is the size for the duct opening measurement only

actual front end outer dimensions are approximately 22" width X 16" height

+ Product Details Perfect Fit & Easy Sizing - Designed for a 20" x 24" OR 24" x 20" duct opening (measured at the opening)

+ Product Description Upgrade your ventilation with our premium grilles and registers

18" x 24" or 24" x 18" Cube Core Eggcrate Return Air Grille Color_R-4.2 Yellow + Product Details Size –+ Product Details Size 18" x 24" or 24" x 18" is the size for the duct opening measurement only, actual front end outer dimensions are approximately 19. 75" X 25. 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