Filters-NOW RH30931 30931 Hunter Air Purifier Filters Fits Hunter models 30212&#44; 30213&#44; 30240&#44; 30241&#44; 30251&#44; 30378&#44; 30379&#44; 30381&#44; Captures airborne particles as small as 0.1 microns from the air. Uses Electrostatically charged filter material. Last up to 6 months under continuous use.