These filters fit 6000, 7000 series full face mask respirator we sell. The reason is that the extremely fine filtration traps all but the most minuscule particles. So our customers use them to protect against lead dusts in particular, as well as a host of other dusts, allergens and fumes. The filters are extremely light weight, flexible and they fit tight against the mask, all of which makes. Wearing this type of mask a bit more comfortable. Due to the light and screen difference, the item’s color may be slightly different from the pictures. 2/4/8/10/20Pcs x 2091CN Filter. 5N11 Filters Item Specifics. Approved for environments containing certain non-oil based particles. 5n11 cotton filter can be used. Function: Resist Non-Oily Particles. Material: High Electrostatic Filter Material. Particulate Cotton Filter: 10.4x 8.3cm. 10/20/40/100Pcs x 5N11 Cotton Filter.