28" x 26" Cube Core Eggcrate Return Air Filter Grille for 1" Filter d + Product Details Size –

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

Adjustable airflow control – Adjustable airflow control: The system allows users to customize the amount of air supply

Actual Filter Size – 13 3/4"w x 5 3/4" x 1"

+ Product Details Size – 32"w X 20"h is the size for the duct opening measurement only

28" x 26" Cube Core Eggcrate Return Air Filter Grille for 1" Filter d + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 28" x 26" OR 26" x 28" duct opening (measured at the opening), with actual outer dimensions of 30. 5" W x 28. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 27. 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