32" x 26" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Material_Aluminum But they are also the

But they are also the most visible representation of you air system

+ Product Details Perfect Fit & Easy Sizing - Designed for a 32" x 36" Or 36" x 32" duct opening (measured at the opening)

75"H – fits a 6" X 4" duct opening

75"H – fits a 20" X 4" duct opening

actual front end outer dimensions are approximately 36 5/8" width X 28 5/8" height

32" x 26" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Material_Aluminum But they are also the+ Product Details Perfect Fit & Easy Sizing Designed for a 32" x 26" OR 26" x 32" duct opening (measured at the opening), with actual outer dimensions of 34. 5" W x 28. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 31. 75" x 25. 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