24" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 14in diameter + Product Details Size -

+ Product Details Size - 18"w X 10"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 6" x 26" or 26" x 6" duct opening (measured at the opening)

Designed with individually adjustable curved blades

+ Product Details Perfect Fit & Easy Sizing - Designed for a 18" x 36" OR 36" x 18" duct opening (measured at the opening)

+ Product Details Perfect Fit & Easy Sizing - Designed for a 8" x 30" or 30" x 8" duct opening (measured at the opening)

24" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 14in diameter + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 24" x 6" OR 6" x 24" duct opening (measured at the opening), with actual outer dimensions of 26. 5" W x 8. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 23. 75" x 5. 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