18" x 36" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Color_Red Oak Actual Filter Size – 31

Actual Filter Size – 31 3/4"w x 21 3/4" x 1"

875" width X 8" height

+ Product Details Perfect Fit & Easy Sizing - Designed for a 26" x 34" OR 34" x 26" duct opening (measured at the opening)

75"H – fits a 24" X 8" duct opening

18" x 36" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Color_Red Oak Actual Filter Size – 31+ Product Details Perfect Fit & Easy Sizing Designed for a 18" x 36" OR 36" x 18" duct opening (measured at the opening), with actual outer dimensions of 20. 5" W x 38. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 17. 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