100% PVC-free, added carbon layer helps filter out nuisance levels of ozone and organic vapors (less than OSHA PEL), can be used against most welding fumes (free of oil), added carbon layer helps relieve against nuisance ozone and organic vapors, exhale valve lets workers breathe easy and stay cool, exclusive Dura-Mesh® shell resists collapsing in heat and humidity, molded nose bridge with soft foam nose cushion increases comfort, facepiece is naturally contoured without pressure points, meets heat and flame resistance in accordance with ANSI/ISEA 110-2003 Section 7.11.1. 10/box