The added carbon layer helps filter out nuisance levels of ozone and organic vapors (less than OSHA PEL). The 2400N95 Particulate Respirator is suitable for most welding applications, and fits easily under welding hoods. Workers stay cooler with an exhale valve that reduces breathing resistance and hot air build up. The exclusive Dura-Mesh shell protects the filter media so it stays cleaner-looking longer. The shell resists collapsing, even in heat and humidity, so the respirator holds its shape longer. The result is fewer respirators used and lower costs. The molded nose bridge and soft foam nose cushion provides the wearer with an easier, more comfortable fit. There's no metal noseband to adjust and the seal is maintained without pressure points. NIOSH certified to have a filter efficiency 95% or greater against particulate aerosols free of oil. This product meets heat and flame resistance in accordance with ANSI/ISEA 110-2003 Section 7.11.1. If used for welding, wear appropriate eye and face protection. (100% PVC Free) Suggested applications: Hot, humid and dusty environments under 10x PEL, i.e. 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, petro-chemical and chemical processing, printing, food processing, tobacco, paint and varnish manufacturing, synthetic rubber manufacturing, undercoating, mortuaries, wast processing and sewage treatment. No oils present. NIOSH approval: TC-84A-0883.