This replacement Miele Active HEPA filter fits S4, S5, S6, and S8 Miele canister vacuums. It features a thin layer of activated charcoal to help trap and remove odors, while true HEPA filtration captures 99.97% of all particles 0.3 microns and larger. A rubber seal around the filter allows it to form an air-tight seal in the vacuum, ensuring all the air is properly filtered. This filter is ideal for allergy and asthma sufferers. Replace annually or after approximately 50 hours of use. Miele part number SF-AH 50.