1.Non-irritating, easier breathing 2. With valve 3.Single use. 4.Made of multi-layered nonpoisonous, non-allergic, non-stimulating materials. 5.Adjust the bandage strip and built-in foam cushion to adapt to various face-shapes with comfortable sealing. 6.High efficient and strong electrostatic filtering materials effectively filter the solid particle dust, and prevent the oil liquid gas. 7.Use for construction, mining, textile, grinding medicine, disintegration projects, cement, agriculture and animal husbandry, cutting dust, pollutes from heavy meta