12" x 34" or 34" x 12" Cube Core Eggcrate Return Air Grille Insulated Line Set + Product Details Perfect Fit

+ Product Details Perfect Fit & Easy Sizing - Designed for a 10" x 20" duct opening (measured at the opening)

Its professional design and solid construction make it the perfect solution for safeguarding your thermostat against unwanted access

Actual Filter Size – 27 3/4"w x 29 3/4" x 1"

+ Product Description Ventilate your home or commercial space with our Aluminum Outdoor Weatherproof Louvers

+ Product Details Size – 14" x 16" or 16" x 14" is the size for the duct opening measurement only

12" x 34" or 34" x 12" Cube Core Eggcrate Return Air Grille Insulated Line Set + Product Details Perfect Fit+ Product Details Size 12" x 34" or 34" x 12" is the size for the duct opening measurement only, actual front end outer dimensions are approximately 13. 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