These 3M 15-0499-99X02 Multi-Gas Organic Vapors Replacement Filter Cartridges for 3M Adflo Powered Air Purifying Respirator (PAPR) (P/N: 16-3301-40) or 3M Adflo Powered Air Purifying Respirator (PAPR) with Speedglas 9002X FlexView HWR Helmet (P/N: 16-1101-21SW). These Adflo OV/SD/CL/HC Filter Cartridges can be "stacked" onto the High-Efficiency HEPA Particulate Filter for additional protection against Organic, Sulfur Dioxide, Chlorine and Hydrogen Chloride Vapors. Sold in packages of 2 filter cartridges.
See TnA Safety, Webster, NY on MacRae's Blue Book