20" x 8" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Color_White actual front end outer dimensions

actual front end outer dimensions are approximately 28 5/8" width X 26 5/8" height

For a visual guide on how to measure your vent hole before ordering a grille

This versatile diffuser is available in 1-way

Noise free components - no vibrating louvers etc

20" x 8" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Color_White actual front end outer dimensions+ Product Details Perfect Fit & Easy Sizing Designed for a 20" x 8" OR 8" x 20" duct opening (measured at the opening), with actual outer dimensions of 22. 5" W x 36. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 19. 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