24" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter white + Product Details Size –

+ Product Details Size – 36"w X 18"h is the size for the duct opening measurement only

+ Product Details Size – 12" x 28" or 28" x 12" is the size for the duct opening measurement only

Durable stamped steel construction ensures long-lasting performance

+ Product Details Size – 14" x 24" or 24" x 14" is the size for the duct opening measurement only

Ideal for Walls & Ceilings: Designed for seamless installation in standard 20" X 10" duct openings

24" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter white + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 24" x 12" OR 12" x 24" duct opening (measured at the opening), with actual outer dimensions of 26. 5" W x 14. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 23. 75" x 11. 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