18" x 36" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Color_Red Oak 5" - SEE BELOW IN

5" - SEE BELOW IN DESCRIPTION HOW TO MEASURE A GRILLE

+ Product Details Outer dimensions: 7

875" width X 8" height

75" width X 31

18" x 36" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Color_Red Oak 5" - SEE BELOW IN+ Product Details Perfect Fit & Easy Sizing Designed for a 18" x 36" OR 36" x 18" duct opening (measured at the opening), with actual outer dimensions of 20. 5" W x 38. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 17. 75" x 35. 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