18" x 24" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Powder Coated enhancing the entire room with

enhancing the entire room with its elegant presence

and the second number represents the height

1/2" - 3119 PSI

75" width X 21

With a 8" diameter for the duct opening measurement

18" x 24" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Powder Coated enhancing the entire room with+ Product Details Perfect Fit & Easy Sizing Designed for a 18" x 24" OR 24" x 18" duct opening (measured at the opening), with actual outer dimensions of 20. 5" W x 26. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 17. 75" x 23. 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