26" x 36" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w18h18 + Product Details Outer dimensions:

+ Product Details Outer dimensions: 17

High Quality – Commercial grade aluminum - will never rust - designed for warehouses

+ Product Details Perfect Fit & Easy Sizing - Designed for a 14" x 10" or 10" x 14" duct opening (measured at the opening)

+ Product Details Size – 25"w X 10"h is the size for the duct opening measurement only

26" x 36" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w18h18 + Product Details Outer dimensions:+ Product Details Perfect Fit & Easy Sizing Designed for a 26" x 36" OR 36" x 26" duct opening (measured at the opening), with actual outer dimensions of 28. 5" W x 38. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 25. 75" x 35. 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