HQRP HEPA Filter 4-Pack for Miele S2120 S2121 S2180 S2181 S401i S412 S428i S434i S444i Canister Vac Vacuum Cleaner Coaster HQRP&reg; Four Filters plus HQRP&reg; Coaster; This Active filter is HEPA and retains 99.97% of particles down to 0.3 micron. The filter has a activated carbon layer to neutralize and absorb odors. 100% Compatible with Original filter; 2 weeks DOA replacement warranty!