28" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 12in diameter + Product Details Size –

+ Product Details Size – 12"w X 10"h is the size for the duct opening measurement only

+ Product Details Size - 24"w X 12"h is the size for the duct opening measurement only

+ Product Details Size - 30"w X 20"h is the size for the duct opening measurement only

+ Product Details Size – 10" x 24" or 24" x 10" is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 24" x 20" OR 20" x 24" duct opening (measured at the opening)

28" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 12in diameter + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 28" x 6" OR 6" x 28" duct opening (measured at the opening), with actual outer dimensions of 30. 5" W x 8. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 27. 75" x 5. 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 Made