10" x 8" or 8" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 12.5" X 10.5"] 12" Round Duct Pipe + Product Details Size -

+ Product Details Size - 10"w X 8"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 15

75"H – fits a 20" X 12" duct opening

Actual Filter Size – 35 3/4"w x 7 3/4" x 1"

10" x 8" or 8" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 12.5" X 10.5"] 12" Round Duct Pipe + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 10" x 8" or 8" x 10" duct opening (measured at the opening), with actual outer dimensions of 12. 5" W x 10. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 9. 75" x 7. 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