Millennium Gas Mask Cannister, 40mm Canister thread, Chemical /Biological/Riot Control Agent and Nuclear. Effective against biological and chemical warfare agents including Tabun, Sarin, Soman, VX, Mustard, Lewisite and are NIOSH approved for protection from Chloroacetophenone (CN), Chlorobenzylidene (CS), P100 particulates. 

MSA Millennium Cannister Features and Specifications

• 40mm NATO threaded low profile design preferred by law enforcement
• Full protection against all known biological and chemical agents
• Third party tested against chemical warfare gases
• Particulate filter is over 99.99% efficient against all particulates and is appropriate for protection against all biological aerosols
• Exceptionally high particle-filtration capacity and low breathing-resistance
• Manufactured in a sealed foil bag
• Standard 40mm NATO threaded
• Six (6) Cannister/Cartridge per box