The 2840 R95 has an added carbon layer for filtering out nuisance levels of ozone and organic vapor odors. The 2940 R95 filters out nuisance levels of acid gases. Includes a HandyStrap®and Ventex® valve for easier breathing, and a Dura-Mesh® shell with a Softspun® lining for added comfort and durability. Certified to be 95% effective against both oil and non-oil based airborne particulates. Certified under NIOSH 42CFR84 Standards for R95.