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

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

+ Product Details Size – 16" x 36" or 36" x 16" is the size for the duct opening measurement only

and with a built-in back 1/2" mesh they also protect you from annoying rodents like mice

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+ Product Details

34" x 36" or 36" x 34" Cube Core Eggcrate Return Air Grille Insulated Line Set + 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