10" x 20" or 20" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 12.5" X 22.5"] 18" Round Duct Pipe + Product Details Size -

+ Product Details Size - 12"w X 20"h is the size for the duct opening measurement only

+ Product Details Size - 26"w X 34"h is the size for the duct opening measurement only

+ Product Details Size – 10" x 10" is the size for the duct opening measurement only

+ Product Details Size – 10"w X 2"h is the size for the duct opening measurement only

10" x 20" or 20" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 12.5" X 22.5"] 18" Round Duct Pipe + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 10" x 20" duct opening (measured at the opening), with actual outer dimensions of 12. 5" W x 22. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 9. 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 Made from