20" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Grille it effectively prevents unauthorized access

it effectively prevents unauthorized access

diagonally feed it through the square hole

actual front end outer dimensions are approximately 36 5/8" width X 10 5/8" height

and versatile for any project

+ Product Details Size – 30"w X 20"h is the size for the duct opening measurement only

20" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Grille it effectively prevents unauthorized access+ Product Details Perfect Fit & Easy Sizing Designed for a 20" x 10" OR 10" x 20" duct opening (measured at the opening), with actual outer dimensions of 22. 5" W x 12. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 19. 75" x 9. 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