Black 5 Layer KN95 dustproof face masks. Bundled in sets of 10 and 50 masks per box. Must be ordered in sets of 50. CDC recommends face coverings to prevent the spread of coronavirus / COVID-19. KN95 masks provide 95% filtering of non-oil based and aerosol particulates greater than 3 microns. Each mask is produced with 3 layers of professional grade non-woven polypropylene and 2 layers of melt-blown microfiber fabric for efficient filtering. The no-valve design has a high filtering and vacuum sealing effect to provide more protection.