8" x 30" or 30" x 8" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 10.5" X 32.5"] 6" Round Duct Pipe actual front end outer dimensions

actual front end outer dimensions are approximately 10 5/8" width X 26 5/8" height

+ Product Details Size – 16" x 18" or 18" x 16" is the size for the duct opening measurement only

actual front end outer dimensions are approximately 12 5/8" width X 30 5/8" height

Adjustable airflow control – Adjustable airflow control: The system allows users to customize the amount of air supply

8" x 30" or 30" x 8" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 10.5" X 32.5"] 6" Round Duct Pipe actual front end outer dimensions+ Product Details Perfect Fit & Easy Sizing Designed for a 8" x 30" or 30" x 8" duct opening (measured at the opening), with actual outer dimensions of 10. 5" W x 32. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 7. 75" x 29. 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