18" x 28" or 28" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Outdoor Vent Covers Actual Filter Size – 24

Actual Filter Size – 24 3/4"w x 25 3/4" x 1"

With these options

please note that the total outer dimensions of the grille measure 7" in diameter

+ Product Details Perfect Fit & Easy Sizing - Designed for a 22" x 32" OR 32" x 22" duct opening (measured at the opening)

18" x 28" or 28" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Outdoor Vent Covers Actual Filter Size – 24+ Product Details Perfect Fit & Easy Sizing Designed for a 18" x 28" OR 28" x 18" duct opening (measured at the opening), with actual outer dimensions of 20. 5" W x 30. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 17. 75" x 27. 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