14" x 18" or 18" x 14" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 8" Round Duct Pipe } li { margin-bottom: 15px

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actual front end outer dimensions are approximately 27 5/8" width X 30 5/8" height

High Quality – Commercial grade aluminum - will never rust - designed for warehouses

14" x 18" or 18" x 14" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 8" Round Duct Pipe } li { margin-bottom: 15px+ Product Details Perfect Fit & Easy Sizing Designed for a 14" x 18" OR 18" X 14" duct opening (measured at the opening), with actual outer dimensions of 16. 5" W x 20. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 13. 75" x 17. 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