Class 3 high efficiency - non toxic dusts, fibres, aqueous mists and oil based mists. APF:20 X workplace exposure limit. Guide to protection: Brick, concrete, ferrous metal fume, MDF hand tools, plaster, rockwool, sandstone, silica, hard wood & soft wood dusts. (R) Reusable, multiple use. (D) Meets the clogging resistance requirements, able to resist clogging in fine dust environments.