18" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Width_20in Actual Filter Size – 29

Actual Filter Size – 29 3/4"w x 35 3/4" x 1"

+ Product Details Size – 28"w X 22"h is the size for the duct opening measurement only

3-cone supply grille

Design – Heavier gauge than needed

18" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Width_20in Actual Filter Size – 29+ Product Details Perfect Fit & Easy Sizing Designed for a 18" x 12" OR 12" X 18" duct opening (measured at the opening), with actual outer dimensions of 20. 5" W x 14. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 17. 75" x 11. 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