Zero Risque Re-usable Men & Women Face Masks are treated with Heiq Viroblock NPJ03. It is a special combination of advanced silver & vesicle technology that has been proven effective against germs like bacteria etc. It has Particle Filtration Efficiency, that helps filter more than 88% of the particles at 0.3 microns (which is 95% for N95) as per the test method ASTM F2299/F2299M-03 (2010) & Bacteria Filtration Efficiency, that helps filter more than 98% of the bacteria (which is 95% for N95) as per the test method ASTM F 2101.