... filtration efficiency(BFE) has reached to 99.1%. This rate is much higher than normal standard of 98%1.Soft, lightweight, comfortable ... , and bacteria6.In laboratories and factories for blocking liquid mists, harmful airborne chemicals and fine particlesSpecification:1.Material:3-Ply 20gsmPP ... machinery face mask with wrap and spot welding,middle ply is filter,blue,17.5*9.5cm