The Philips Nano Protect HEPA filter of the series 3 consists of high-quality material. He captures up to 99.97% of all particles with a size of up to 0.3 um-the size of the most common allergens, harmful particles in the air, bacteria and viruses. The high-quality filter with strong, sturdy structure guarantees that the whole air through the filter flows, and delivers a high filter performance.