34" x 36" or 36" x 34" Cube Core Eggcrate Return Air Grille w26h26 + Product Details Size –

+ Product Details Size – 20" x 22" or 22" x 20" is the size for the duct opening measurement only

+ Product Details Size – 18"w X 32"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 8" x 26" or 26" x 8" duct opening (measured at the opening)

+ Product Details Size - 16"w X 22"h is the size for the duct opening measurement only

34" x 36" or 36" x 34" Cube Core Eggcrate Return Air Grille w26h26 + Product Details Size –+ Product Details Size 34" x 36" or 36" x 34" is the size for the duct opening measurement only, actual front end outer dimensions are approximately 35. 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