Replacement HEPA Filter Compatible with Blueair 200/300 Series Air Purifiers. Compatible Models include: 201, 203, 203C, 205C, 210B, 215B, 250E, 270, 270E, 303, Part # 200PF, 201PF. True HEPA filtration captures particles as small as 0.3 microns from the air passing through the filter, resulting in cleaner and more breathable air. For maximum efficiency, it is recommended replacing filter every 6 months (dependent on air quality and use).