22" x 36" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Aluminum + Product Details Size –

+ Product Details Size – 18" x 28" or 28" x 18" is the size for the duct opening measurement only

actual front end outer dimensions are 3"

+ Product Details Size – 8"w X 6"h is the size for the duct opening measurement only

+ Product Details Outer dimensions: 17

22" x 36" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Aluminum + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 22" x 36" OR 36" x 22" duct opening (measured at the opening), with actual outer dimensions of 24. 5" W x 38. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 21. 75" x 35. 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