inner, middle and outer layers, the inner layer is ordinary non-woven fabric, the middle layer is ultra-fine polypropylene fiber melt- blown fabric, and
the outer layer is non-woven fabric or ultra-thin polypropylene melt-blown fabric. The ear strap is made of elastic band, which is made of non-wovenfabric with an elastic band inside; the material of the nose strip is a metal strip, which is covered with fine galvanized iron wire material. |