Miele activated carbon for odor control with AirClean particle filter. Fits Miele S4, S5, S6, and S8 canister vacuums. Now with Timestrip technology, the filter will let you know when it needs to be changed. How The Miele Active Filter Works: The SF-AA50 is filled with carbon which helps absorb gas and odors before exhausting from the vacuum. The carbon is sandwich between two Super Airclean filters that will filter out any small particles not trapped by the bag.