Miele HA-50 HEPA filter fits in S4000-S6000 series, S8000 series, Complete C2-C3, Compact C1-C2 Miele vacuums. This filter has a true HEPA filtration layer that removes 99.95%+ of microns .1 or greater in size. Retains 99.95% of all particles/allergens such as viruses and bacteria. Combined with a rubber air tight sealing system around the sides of the filter, you have the ideal setup for allergy sufferers or anyone looking to enjoy a higher quality of air in their home. To help users remember when to change their filters, a time release color strip has been added. Press on arrow on timestrip when fitting filter. The filter is saturated and should be replaced when the indicator strip turns red along its entire length.