18" x 20" or 20" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Round Damper Ring + Product Details Perfect Fit

+ Product Details Perfect Fit & Easy Sizing - Designed for a 8" x 22" or 22" x 8" duct opening (measured at the opening)

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

Say goodbye to pest-related worries as the built-in back 1/2" mesh acts as a barrier against unwanted rodents like mice

Achieve the perfect airflow with adjustable control by rotating the middle disk

Actual Filter Size – 25 3/4"w x 9 3/4" x 1"

18" x 20" or 20" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Round Damper Ring + Product Details Perfect Fit+ 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