20" x 28" or 28" x 20" Cube Core Eggcrate Return Air Grille Round Damper Ring + Product Details Size –

+ Product Details Size – 25"w X 28"h is the size for the duct opening measurement only

+ Product Details Size – 29"w X 22"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 16 5/8" width X 12 5/8" height

+ Product Details Size – 24"w X 36"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 27 5/8" width X 27 5/8" height

20" x 28" or 28" x 20" Cube Core Eggcrate Return Air Grille Round Damper Ring + Product Details Size –+ Product Details Size 20" x 28" or 28" x 20" is the size for the duct opening measurement only, actual front end outer dimensions are approximately 21. 75" X 29. 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