Review on Flintar 2-Pack of H13 Grade True HEPA Replacement Filters, Compatible with LEVOIT Core 300, Core 300S VortexAir Air Purifier, 3-in-1 True HEPA Filter Replacement, Core 300-RF by Ans Brownlee

The description says they are 'compatible' with the Levoit air purifier. What does that mean? Yes, they fit perfectly and are identical to the original Levoit filters. But they seem to offer more resistance to airflow than Levith's. I compared a brand new Levoit filter to this one and found that these (cheaper) filters had reduced airflow and higher fan noise. Fan noise is higher because it has to work harder to push air through the filter. While reducing airflow may not seem like a lot, over time, how much air is flowing through and filtered in a room will make a big difference. I am returning these filters to Flintar and buying original Levoit.