34" x 26" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Color_R-4.2 Yellow + Product Details Size -

+ Product Details Size - 34"w X 36"h is the size for the duct opening measurement only

12" Diameter Is The Size For The Duct Opening Measurement Only

75"H – fits a 20" X 8" duct opening

+ Product Details Size - 16"w X 30"h is the size for the duct opening measurement only

34" x 26" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Color_R-4.2 Yellow + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 34" x 26" Or 26" x 34" duct opening (measured at the opening), with actual outer dimensions of 36. 5" W x 28. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 33. 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