Certified by NIOSH to provide at least 95% filter efficiency against particulate aerosols free of oil. Suggested applications include dusty environments, grinding, sanding, sweeping, bagging, stone quarrying, metal machining, cement, underground mining, polishing, buffing, lime, poultry, textiles. Collapse resistant, Dura-Mesh shell lasts longer so workers use fewer masks. Flame-retardants added to shell to help decrease flammability, contoured nose bridge. 20 per box.