20" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w18h18 actual front end outer dimensions

actual front end outer dimensions are approximately 12 5/8" width X 10 5/8" height

Its linear bar design maximizes ventilation

The total outer size of this grille is the listed size plus 2 and 5/8"

360-Degree Airflow: Experience optimal air circulation like never before

+ Product Details Size – 18" Wooden Corner Baseboard Grille

20" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w18h18 actual front end outer dimensions+ Product Details Perfect Fit & Easy Sizing Designed for a 20" x 18" OR 18" x 20" duct opening (measured at the opening), with actual outer dimensions of 22. 5" W x 20. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 19. 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