Compatible Particle and Activated Carbon Replacement Filter for BLUEAIR Blue Pure 121Premium HEPA filter compatible with Blueair Models 201, 203, 205, 215B, 250E, 270E, and 303 air purifiers It replaces original Blueair 200 300 Series Particle Replacement Filter HEPA filter helps capture up to 99. 97 percent of airborne particles as small as 0. 3 microns. One filter can last from 6 months to a year based on normal use. Quality meets and exceeds leading national brand. r