36" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Compatible with Duct 6" + Product Details Perfect Fit

+ Product Details Perfect Fit & Easy Sizing - Designed for a 12" x 16" or 16" x 12" duct opening (measured at the opening)

When you're ready for a decor upgrade

+ Product Details Size – 10"w X 28"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 20" x 36" OR 36" x 20" duct opening (measured at the opening)

36" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Compatible with Duct 6" + Product Details Perfect Fit+ Product Details Perfect Fit & Easy Sizing Designed for a 36" x 12" OR 12" x 36" duct opening (measured at the opening), with actual outer dimensions of 38. 5" W x 14. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 35. 75" x 11. 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