Miele's patented Type GN FilterBags™ feature 9 layers of electrostatically-charged material and a spring-loaded, self-locking collar. They hold 4.76 quarts of dry debris. The AirClean™ HEPA HA50 filter retains 99.99% of dust, dander, allergens and other lung-damaging particles. It is ideal for allergy and asthma sufferers and only needs to be replaced approximately once a year. The performance pack includes 16 Miele Type GN FilterBags™ and 1 AirClean™ HEPA HA50 filter.