20" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 10in diameter Its professional design and solid

Its professional design and solid construction make it the perfect solution for safeguarding your thermostat against unwanted access

And The Cooler Air From Outside WIll Flow In From The Bottom

actual front end outer dimensions are approximately 29

[Outer Dimensions: 50

+ Product Details Size - 12"w X 30"h is the size for the duct opening measurement only

20" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 10in diameter Its professional design and solid+ 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