18" x 30" or 30" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Aluminum Adjustable Curved Blade + Product Details Size –

+ Product Details Size – 6" x 34" or 34" x 6" is the size for the duct opening measurement only

actual front end outer dimensions are approximately 14 5/8" width X 28 5/8" height

75" Width X 26

actual front end outer dimensions are approximately 20 5/8" width X 32 5/8" height -

actual front end outer dimensions are approximately 36 5/8" width X 26 5/8" height

18" x 30" or 30" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Aluminum Adjustable Curved Blade + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 18" x 30" OR 30" x 18" duct opening (measured at the opening), with actual outer dimensions of 20. 5" W x 32. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 17. 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