The 3M 2091 P100 (HEPA) Filter is sold by the pair and features extremely fine filtration that traps all but the most minuscule particles. Our customers use them to protect against asbestos and lead dusts in particular, as well as a host of other dusts, allergens and fumes. The filters are extremely lightweight and flexible, and they fit tight against the mask, which makes wearing this type of mask a bit more comfortable.
The 3M 2091 P100 Filters fit on the 3M 6000 and 3M 7500 series half masks, as well as the 3M 6000 full face respirators. HEPA filtration is rated to remove 99.9% of particles .3 microns and larger. This includes most welding fumes (burnt metal), toxic dusts like asbestos and lead, and folks with allergies to many environmental dusts. Sometimes called a 3M P100 pancake filter, they are attached directly to the mask. A simple 1/4 turn locks them on. No retainers or other attachment methods are needed.