18" x 20" or 20" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Round Damper Ring actual front end outer dimensions

actual front end outer dimensions are approximately 20 5/8" width X 27 5/8" height -

+ Product Details Size - 28"w X 24"h is the size for the duct opening measurement only

or office environments

we cater to your needs

These are built heavy duty for installation into brick and cement walls

18" x 20" or 20" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Round Damper Ring actual front end outer dimensions+ Product Details Perfect Fit & Easy Sizing Designed for a 18" x 20" OR 20" x 18" duct opening (measured at the opening), with actual outer dimensions of 20. 5" W x 22. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 17. 75" x 19. 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