20" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Grilles as the multidirectional design ensures

as the multidirectional design ensures consistent temperature control

Actual Filter Size – 11 3/4"w x 5 3/4" x 1"

Tamper-Proof Design – Provides robust protection to prevent unauthorized access and ensure consistent thermostat settings

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+ Product Details Size – 36"w X 28"h is the size for the duct opening measurement only

20" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Grilles as the multidirectional design ensures+ Product Details Perfect Fit & Easy Sizing Designed for a 20" x 12" OR 12" x 20" duct opening (measured at the opening), with actual outer dimensions of 22. 5" W x 14. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 19. 75" x 11. 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