34" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 8" Round Duct Pipe + Product Details Size –

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

For 14" Round Duct Opening - Spiral or Flex

+ Product Details Size – 18"w X 16"h is the size for the duct opening measurement only

+ Product Details Size – 20"w X 40"h is the size for the duct opening measurement only

Actual Filter Size – 29 3/4"w x 17 3/4" x 1"

34" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 8" Round Duct Pipe + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 34" x 10" Or 10" x 34" duct opening (measured at the opening), with actual outer dimensions of 36. 5" W x 12. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 33. 75" x 9. 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