Added carbon layer helps filter out nuisance levels of ozone and organic vapors (less than OSHA PEL). For most welding applications. Exhale valve reduces hot air build-up to keep workers cooler. Dura-Mesh® shell resists collapsing lasts longer so workers use fewer masks. Flame retardants are added to the shell to help decrease flammability. Contour molded nose bridge with soft foam nose flange provides all-day comfort. Softspun® lining increases comfort and durability. NIOSH certified to have a filter efficiency of 95% or greater against particulate aerosols free of oil. Applications: Hot, humid and dusty environments such as welding, soldering and brazing, grinding, sanding, sweeping, bagging, stone quarrying, metal machining, cement, underground mining, polishing, buffing, lime, poultry and textiles. Welding and foundry operations, lab settings, agriculture, chemical processing, printing, food processing, paint and varnish manufacturing, waste processing and sewage treatment. No oils present.