Exhale valve reduces hot-air build-up. Keeps worker cooler and more comfortable. Collapse-resistant Dura-Mesh™ Shell lasts longer so workers use fewer masks. Flame-retardants added to help decrease flammability of shell. Shaped for comfort with contour molded nose-bridge. Soft foam nose seal fits easily and comfortably without a metal nose band. Certified under NIOSH 42CFR84 to have filter efficiency level of 99% or greater against particulate aerosols free of oil. Approval: 84A-1459