30" x 30" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Compatible With Duct 12in + Product Details Perfect Fit

+ Product Details Perfect Fit & Easy Sizing - Designed for a 10" x 18" or 18" x 10" duct opening (measured at the opening)

+ Product Details Perfect Fit & Easy Sizing - Designed for a 8" x 14" or 14" x 8" duct opening (measured at the opening)

For 14" Round Duct Opening - Spiral or Flex

+ Product Details Size - 25"w X 18"h is the size for the duct opening measurement only

30" x 30" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Compatible With Duct 12in + Product Details Perfect Fit+ Product Details Perfect Fit & Easy Sizing Designed for a 30" x 30" duct opening (measured at the opening), with actual outer dimensions of 32. 5" W x 32. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 29. 75" x 29. 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 Made from