18" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 6in diameter actual front end outer dimensions

actual front end outer dimensions are approximately 27 5/8" width X 38 5/8" height

actual front end outer dimensions are approximately 26

Perfectly suited for both residential and commercial use

you can attain the diameter of the vent

18" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 6in diameter actual front end outer dimensions+ Product Details Perfect Fit & Easy Sizing Designed for a 18" x 10" OR 10" X 18" duct opening (measured at the opening), with actual outer dimensions of 20. 5" W x 10. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 17. 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