36" x 26" Cube Core Eggcrate Return Air Filter Grille for 1" Filter RV Mobile Home + Product Details Size –

+ Product Details Size – 12" x 20" or 20" x 12" is the size for the duct opening measurement only

+ Product Details Size - 14"w X 36"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 12 5/8" width X 20 5/8" height

Filter Size - 27

+ Product Details Size - 12"w X 14"h is the size for the duct opening measurement only

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