10" x 16" or 16" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 12.5" X 18.5"] 10" Diameter See chart below:

See chart below:

Actual Filter Size – 17 3/4"w x 23 3/4" x 1"

Install 2 Vents

both individually adjustable

10" x 16" or 16" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 12.5" X 18.5"] 10" Diameter See chart below:+ Product Details Perfect Fit & Easy Sizing Designed for a 10" x 16" or 16" x 10" duct opening (measured at the opening), with actual outer dimensions of 12. 5" W x 18. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 9. 75" x 15. 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