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

+ Product Details Perfect Fit & Easy Sizing - Designed for a 30" x 16" OR 16" x 30" duct opening (measured at the opening)

+ Product Details Outer dimensions: 11

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

Ideal for Walls & Ceilings: Designed for seamless installation in standard 10" X 10" duct openings

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