12" x 30" or 30" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Compatible With Duct 8in + Product Details Size -

+ Product Details Size - 30"w X 18"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 10 5/8" width X 30 5/8" height

efficient airflow

Suitable for all AC applications

actual front end outer dimensions are approximately 10 5/8" width X 28 5/8" height

12" x 30" or 30" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Compatible With Duct 8in + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 12" x 30" or 30" x 12" duct opening (measured at the opening), with actual outer dimensions of 14. 5" W x 32. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 11. 75" x 29. 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