10" x 18" or 18" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 12.5" X 20.5"] Curved Blade Steel + Product Details Size –

+ Product Details Size – 16"w X 36"h is the size for the duct opening measurement only

Equipped with a locking eight-tumbler key system

baffles and plaster frames available

please note that the total outer dimensions of the grille measure 12" in diameter

875" width X 16" height

10" x 18" or 18" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 12.5" X 20.5"] Curved Blade Steel + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 10" x 18" or 18" x 10" duct opening (measured at the opening), with actual outer dimensions of 12. 5" W x 20. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 9. 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