12" x 14" or 14" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 14.5" X 16.5"] w8h8 + Product Details Size -

+ Product Details Size - 18"w X 4"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 22 5/8" width X 10 5/8" height

With precise measurements for seamless integration

6" width X 11

+ Product Details Size - 22"w X 4"h is the size for the duct opening measurement only

12" x 14" or 14" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 14.5" X 16.5"] w8h8 + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 12" x 14" or 14" x 12" duct opening (measured at the opening), with actual outer dimensions of 14. 5" W x 16. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 11. 75" x 13. 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