6" x 18" or 18" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 8.5" X 20.5"] Compatible with Duct 6" [Outer Dimensions: 32

[Outer Dimensions: 32

actual front end outer dimensions are approximately 36 5/8" width X 36 5/8" height

actual front end outer dimensions are approximately 18 5/8" width X 28 5/8" height

actual front end outer dimensions are approximately 20 5/8" width X 22 5/8" height -

6" x 18" or 18" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 8.5" X 20.5"] Compatible with Duct 6" [Outer Dimensions: 32+ Product Details Perfect Fit & Easy Sizing Designed for a 6" x 18" or 18" x 6" duct opening (measured at the opening), with actual outer dimensions of 8. 5" W x 20. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 5. 75" x 17. 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