The Miele Active HEPA Filter (HA 50) not only captures and retains tiny, lung-damaging particles (including dust mite feces and pollen), it also uses activated charcoal to filter to absorb odors. This Miele filter conforms to the new stringent European standard for filtration (EN 1822), which means that it actually traps 99.99% of all particles as tiny as 0.3 microns. The Miele HA-50 HEPA AirClean filter needs to be replaced after 50 hours of use, or approximately 12 months. Once activated, a time strip releases a red line of liquid over the course of one year, which takes the guesswork out of when the filter should be replaced. Designed for Miele S4, S5, S6 and S8 series canister vacuum cleaners. Miele product number 09616280.