Dura-Meshｮ shell protects the filter media so that it stays cleaner-looking longer. Shell resists collapsing, even in heat and humidity. Softspunｮ lining gives added comfort and durability. Contour molded nosebridge with a soft foam nose cushion for an easy comfortable fit. The 2300N95 Series features an exhale valve and is suitable for most welding applications. The exhale valve reduces hot air buildup, reducing breathing resistance and keeping workers cooler longer. The 2400N95 Series has an added carbon layer to help filter out nuisance levels of ozone and organic vapors (less than OSHA PEL). Suitable for most welding applications and fits easily under welding hoods. No metal noseband to adjust and the seal is maintained without pressure points. Straps are securely attached to avoid breakage at the seal. The 2500N95 has an added carbon layer to help filter out nuisance levels of acid gases (less than OSHA PEL). All meet heat and flame resistance in accordance with ANSI/ISEA 110-2003, Section 7.11.1.