Dust Replacement Cartridges, specifically the 3M 2091 High Efficiency Particulate Filter P100 , are 2091 Particulate filter designed for protecting against particulates and airborne dust. Meets the toughest of the new NIOSH 42 CFR 84 filtration classifications. It is the most protective 6000 series filter we offer. Suitable for all applications. 3M-2091 sold in 2-Pack. Ideal for sanding, dust-environments, hay, etc.