8" x 8" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 10.5" X 10.5"] 3-Way or 4-Way If your duct opening is

If your duct opening is 14 inches in diameter

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

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

with actual outer dimensions of 26

8" x 8" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 10.5" X 10.5"] 3-Way or 4-Way If your duct opening is+ Product Details Perfect Fit & Easy Sizing Designed for a 8" x 8" duct opening (measured at the opening), with actual outer dimensions of 10. 5" W x 10. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 7. 75" x 7. 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 Made from strong,