6" x 10" or 6" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 8.5" X 12.5"] 6" Round Duct Pipe + Product Details Size -

+ Product Details Size - 30"w X 25"h is the size for the duct opening measurement only

+ Product Details Size - 8"w X 24"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 6" x 12" or 12" x 6" duct opening (measured at the opening)

+ Product Details Size - 24"w X 26"h is the size for the duct opening measurement only

Actual Filter Size – 31 3/4"w x 19 3/4" x 1"

6" x 10" or 6" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 8.5" X 12.5"] 6" Round Duct Pipe + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 6" x 10" or 10" x 6" duct opening (measured at the opening), with actual outer dimensions of 8. 5" W x 12. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 5. 75" x 9. 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