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

+ Product Details Size – 40"w X 10"h is the size for the duct opening measurement only

+ Product Details Size - 26"w X 30"h is the size for the duct opening measurement only

Ideal for Walls & Ceilings: Designed for seamless installation in standard 16" X 6" duct openings

and centralized air ducted units

24" x 28" Cube Core Eggcrate Return Air Filter Grille for 1" Filter steel + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 24" x 28" OR 28" x 24" duct opening (measured at the opening), with actual outer dimensions of 26. 5" W x 30. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 23. 75" x 27. 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