28" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 12" Round Duct Pipe Actual Filter Size – 35

Actual Filter Size – 35 3/4"w x 21 3/4" x 1"

+ Product Details Size - 18"w X 36"h is the size for the duct opening measurement only

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Installation Location – sidewall and ceiling

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28" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 12" Round Duct Pipe Actual Filter Size – 35+ Product Details Perfect Fit & Easy Sizing Designed for a 28" x 10" OR 10" x 28" duct opening (measured at the opening), with actual outer dimensions of 30. 5" W x 12. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 27. 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