... factory is engaged in the production and sales of loudspeaker diaphragms,with a great variety of products and a complete range ... ,including silk ,POLYESTER, ALUMINUM, TITANIUM, MALAR ,PEI, PEN AND PU diaphragms and dust caps,ranging from 13 cores to 100 cores ... engaged in the research and development of various types of diaphragms and dust caps.All the materials used for the products ...