2 Pack, Multi-Purpose Respirator Replacement Cartridges, OV/AG/P100, Approved For P100 Filter Class As Well As Ammonia, Organic Vapors, Chlorine, Hydrogen Chloride, Chlorine Dioxide, Sulphur Dioxide, Hydrogen Sulfide For Escape Only, Formaldehyde, Hydrogen Fluoride & Methylamine Gases, Used In MSA #SWX00320 Multi-Purpose Respirator Half Mask.