6" x 18" or 18" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 8.5" X 20.5"] Compatible with Duct 10" #hvac-product-accordion { border: 2px solid

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+ Why HVAC Premium

Actual Filter Size – 27 3/4"w x 35 3/4" x 1"

+ Product Details Size – 12" x 20" or 20" x 12" is the size for the duct opening measurement only

6" x 18" or 18" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 8.5" X 20.5"] Compatible with Duct 10" #hvac-product-accordion { border: 2px solid+ Product Details Perfect Fit & Easy Sizing Designed for a 6" x 18" or 18" x 6" duct opening (measured at the opening), with actual outer dimensions of 8. 5" W x 20. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 5. 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 Made