The Active HEPA 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.
Replace after 50 hrs. of use which is approximately once a year if you vacuum one hour per week.

Fits the following models:

S300-S600, S2 canisters
S7 uprights

Contains: 1 filter