32" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Material_Steel + Product Details Size -

+ Product Details Size - 26"w X 26"h is the size for the duct opening measurement only

diagonally feed it through the square hole

+ Product Details Perfect Fit & Easy Sizing - Designed for a 16" x 36" OR 36" X 16" duct opening (measured at the opening)

Actual Filter Size – 11 3/4"w x 7 3/4" x 1"

32" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Material_Steel + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 32" x 18" OR 18" x 32" duct opening (measured at the opening), with actual outer dimensions of 34. 5" W x 20. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 31. 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