DESC: Fits Miele Galaxy models S4000 series. The Active H.E.P.A. (High-Efficiency Particulate Air) filter not only captures and retains tiny, lung-damaging particles (including dust mite feces and pollen), it also uses the same Generally Activated Charcoal filter (GAC) that the Active Air Clean filter uses to absorb odors. Captures and retains 99.5% of all particles as small as 0.3 micron. Replacing the HEPA filter at least once a year is recommended.