18" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 8in diameter it's built to last and

it's built to last and will never rust

+ Product Details Size - 32"w X 8"h is the size for the duct opening measurement only

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+ Product Details Size - 3" Diameter is the size for the duct opening measurement only

18" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 8in diameter it's built to last and+ Product Details Perfect Fit & Easy Sizing Designed for a 18" x 6" OR 6" X 18" duct opening (measured at the opening), with actual outer dimensions of 20. 5" W x 8. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 17. 75" x 5. 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