6" x 28" or 28" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 8.5" X 30.5"] Grilles + Product Details Size -

+ Product Details Size - 6"w X 4"h is the size for the duct opening measurement only

crafted from heavy gauge steel for unparalleled durability

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+ Product Details Size – 12"w X 30"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 10" x 14" or 14" x 10" duct opening (measured at the opening)

6" x 28" or 28" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 8.5" X 30.5"] Grilles + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 6" x 28" or 28" x 6" duct opening (measured at the opening), with actual outer dimensions of 8. 5" W x 30. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 5. 75" x 27. 75" x 1" Premium Airflow Efficiency High performance cube core eggcrate design allows 95% airflow efficiency, reducing energy costs and maximizing HVAC system lifespan. Durable, Rust Free Aluminum Made