This Genuine Miele HEPA Filter is designed to retain 99.97% of pollens, household dust, dust mite droppings and other allergens as small as 0.3 ?m in size. The fan-fold design provides a very large filter media area to enhance air flow. This filter is recommended for those who have dust related allergies or asthma. It was used in Miele S179-S185 Powerhouse uprights.