14" x 20" or 20" x 14" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 16.5" X 22.5"] Color_R-8.0 Pink + Product Details Size -

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

+ Product Details Size - 36"w X 10"h is the size for the duct opening measurement only

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+ Product Details Size – 14"w X 24"h is the size for the duct opening measurement only

14" x 20" or 20" x 14" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 16.5" X 22.5"] Color_R-8.0 Pink + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 14" x 20" OR 20" X 14" duct opening (measured at the opening), with actual outer dimensions of 16. 5" W x 22. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 13. 75" x 19. 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