26" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Aluminum - Cube Core padding: 14px 14px 6px 46px

padding: 14px 14px 6px 46px

Actual Filter Size – 31 3/4"w x 35 3/4" x 1"

+ Product Details Perfect Fit & Easy Sizing - Designed for a 18" x 16" OR 16" X 18" duct opening (measured at the opening)

actual front end outer dimensions are 13

you can watch this informative video tutorial: How to Measure Your Vent Hole Before Ordering a Grille

26" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Aluminum - Cube Core padding: 14px 14px 6px 46px+ Product Details Perfect Fit & Easy Sizing Designed for a 26" x 18" OR 18" x 26" duct opening (measured at the opening), with actual outer dimensions of 28. 5" W x 20. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 25. 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