10" x 12" or 12" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 12.5" X 14.5"] w28h28 + Product Details Size -

+ Product Details Size - 24"w X 4"h is the size for the duct opening measurement only

+ Product Details Size – 14" X 4" is the size for the duct opening (floor/vent hole) measurement only

+ Product Details Size – 28"w X 36"h is the size for the duct opening measurement only

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

10" x 12" or 12" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 12.5" X 14.5"] w28h28 + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 10" x 12" or 12" x 10" duct opening (measured at the opening), with actual outer dimensions of 12. 5" W x 14. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 9. 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