36" x 30" Cube Core Eggcrate Return Air Filter Grille for 1" Filter ceiling + Product Details Perfect Fit

+ Product Details Perfect Fit & Easy Sizing - Designed for a 20" x 18" OR 18" x 20" duct opening (measured at the opening)

+ Product Details Perfect Fit & Easy Sizing - Designed for a 34" x 24" Or 24" x 34" duct opening (measured at the opening)

actual front end outer dimensions are approximately 18 5/8" width X 32 5/8" height -

+ Product Details Perfect Fit & Easy Sizing - Designed for a 8" x 26" or 26" x 8" duct opening (measured at the opening)

36" x 30" Cube Core Eggcrate Return Air Filter Grille for 1" Filter ceiling + Product Details Perfect Fit+ Product Details Perfect Fit & Easy Sizing Designed for a 36" x 30" OR 30" x 36" duct opening (measured at the opening), with actual outer dimensions of 38. 5" W x 32. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 35. 75" x 29. 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