28" x 36" or 36" x 28" Cube Core Eggcrate Return Air Grille Grille each diffuser is carefully shrink-wrapped

each diffuser is carefully shrink-wrapped with a sturdy cardboard backing

actual front end outer dimensions are approximately 34 5/8" width X 24 5/8" height

with actual outer dimensions of 10

providing a perfect fit for most standard thermostats

28" x 36" or 36" x 28" Cube Core Eggcrate Return Air Grille Grille each diffuser is carefully shrink-wrapped+ 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