24" x 36" or 36" x 24" Cube Core Eggcrate Return Air Grille Compatible With Duct 8in + Product Details Size -

+ Product Details Size - 4"w X 18"h is the size for the duct opening measurement only

engineered for seamless 360-degree airflow in T-bar ceilings

+ Product Details Perfect Fit & Easy Sizing - Designed for a 18" x 18" duct opening (measured at the opening)

actual front end outer dimensions are approximately 26 5/8" width X 26 5/8" height

actual front end outer dimensions are approximately 36 5/8" width X 8 5/8" height

24" x 36" or 36" x 24" Cube Core Eggcrate Return Air Grille Compatible With Duct 8in + Product Details Size -+ Product Details Size 24" x 36" or 36" x 24" is the size for the duct opening measurement only, actual front end outer dimensions are approximately 25. 75" X 37. 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