Philips' NanoProtect HEPA filter was designed for the air purifier Series 3000. It has multiple optimised pleats that cover an unfolded area of about 2m2 to ensure a long lifetime of 24 months. It can capture up to 99.97% of particles, including those as small as 0.3 microns—the size of most common airborne allergens, harmful particles, bacteria and viruses.