34" x 28" Cube Core Eggcrate Return Air Filter Grille for 1" Filter return grille + Product Details Size –

+ Product Details Size – 26" x 36" or 36" x 26" is the size for the duct opening measurement only

+ Product Details Size – 10"w X 16"h is the size for the duct opening measurement only

Tough reinforced metallized polyester jacket - tear and puncture resistant

+ Product Details Size - 18"w X 14"h is the size for the duct opening measurement only

+ Product Details Size – 12"w X 18"h is the size for the duct opening measurement only

34" x 28" Cube Core Eggcrate Return Air Filter Grille for 1" Filter return grille + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 34" x 28" Or 28" x 34" duct opening (measured at the opening), with actual outer dimensions of 36. 5" W x 30. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 33. 75" x 27. 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