... free synthetic rubber head strap. 3.Staple free optional Facial Mask, Dust Mask, Masks Features1. Conforms to international standards: EN149: ... processing, cement textile, disintegration, carving, heavy metal pollution, gardening, glass, workshops, etc. Package1. Box: 20pcs/box,20 box/carton, ... partical filtration efficiency and the shape of mask according to customer's demand in details. Facial Mask