24" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Fixed Blades with Damper Ideal for Walls & Ceilings:

Ideal for Walls & Ceilings: Designed for seamless installation in standard 20" X 18" duct openings

Multi-shutter damper with easy lever for precise airflow control

+ Product Details Size – 6" x 26" or 26" x 6" is the size for the duct opening measurement only

+ Product Details Size - 14"w X 25"h is the size for the duct opening measurement only

24" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Fixed Blades with Damper Ideal for Walls & Ceilings:+ Product Details Perfect Fit & Easy Sizing Designed for a 24" x 18" OR 18" x 24" duct opening (measured at the opening), with actual outer dimensions of 26. 5" W x 20. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 23. 75" x 17. 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