28" x 36" or 36" x 28" Cube Core Eggcrate Return Air Grille Grille + Product Details Size –

+ Product Details Size – 18"w X 22"h is the size for the duct opening measurement only

providing a perfect fit for most standard thermostats

Its durability and performance contribute to overall comfort

For 14" duct opening

28" x 36" or 36" x 28" Cube Core Eggcrate Return Air Grille Grille + Product Details Size –+ Product Details Size 28" x 36" or 36" x 28" is the size for the duct opening measurement only, actual front end outer dimensions are approximately 29. 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