36" x 36" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w20h20 + Product Details Perfect Fit

+ Product Details Perfect Fit & Easy Sizing - Designed for a 10" x 34" or 34" x 10" duct opening (measured at the opening)

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

+ Product Details Perfect Fit & Easy Sizing - Designed for a 28" x 32" OR 32" x 28" duct opening (measured at the opening)

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36" x 36" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w20h20 + Product Details Perfect Fit+ Product Details Perfect Fit & Easy Sizing Designed for a 36" x 36" duct opening (measured at the opening), with actual outer dimensions of 38. 5" W x 38. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 35. 75" x 35. 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