... 3.Adjustable nosepiece 4.good quality and reasonable price Dust mask straps style design to make more comfortable to wear, ... more fitting for a variety of face.Advantages; ventilation, dust, bacteria filter, no particles ultrasonic sealing edge, wear comfortable ... health.Scope; medical, anti-flu, avian influenza, swine flu prevention, anti-H1N1, food hygiene, electronics, dust-free clean rooms, public ...