18" x 24" Cube Core Eggcrate Return Air Filter Grille for 1" Filter White Each grille is carefully packaged

Each grille is carefully packaged with cardboard backing to prevent damage during shipment

Actual Filter Size – 11 3/4"w x 11 3/4" x 1"

+ Product Details Size - 18"w X 20"h is the size for the duct opening measurement only

+ Product Details Size - 16"w X 25"h is the size for the duct opening measurement only

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