99% BACTERIAL FILTRATION EFFICIENCY, over 99% Nelson Report 1,Using super adsorption pollen, dirt and other small particles of non-woven fabrics,Three-layer filtering2,Due to mix into the nose and a fixed role, so easy rope loose, also can make the nose of the crack side up3,Because it is stereo processing, so it can avoid the mouth, nose, tighten breathing difficulties uncomfortable feeling4,Due ...