26" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w34h34 + Product Details Size –

+ Product Details Size – 28"w X 18"h is the size for the duct opening measurement only

+ Product Details Size - 36"w X 30"h is the size for the duct opening measurement only

Actual Front End Outer Dimensions Are 14" Diameter

+ Product Description This aluminum flex duct is intended to be used in heating

26" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w34h34 + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 26" x 10" OR 10" x 26" duct opening (measured at the opening), with actual outer dimensions of 28. 5" W x 12. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 25. 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