32" x 34" or 34" x 32" Cube Core Eggcrate Return Air Grille 18in diameter + Product Details Size –

+ Product Details Size – 12"w X 4"h is the size for the duct opening measurement only

1/2" White insulation will give you a good R value of 3

+ Product Details Size - 22"w X 10"h is the size for the duct opening measurement only

Seamless Installation: Designed to fit seamlessly into a 24 by 24 inch opening

actual front end outer dimensions are approximately 10 5/8" width X 38 5/8" height

32" x 34" or 34" x 32" Cube Core Eggcrate Return Air Grille 18in diameter + Product Details Size –+ Product Details Size 32" x 34" or 34" x 32" is the size for the duct opening measurement only, actual front end outer dimensions are approximately 33. 75" X 35. 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