Moldex N99 Premium Particuatle Respirator for most welding applications. Exhale valve reduces hot air buildup for added comfort. Dura-Mesh shell resists collapsing in hot, humid environments. Flame-retardants added to the shell to decrease flammability. Shaped for comfort with contour molded nose bridge and soft foam nose flange. Softspun lining increases comfort and durability. NIOSH certified to have a filter efficiency of 99 percent or greater against particulates free of oil. Box of 10.