Silk, nowadays almost exclusively made in East Asian countries and China (though very much manufactured in the Como area), is a silky filament yarn spun by silkworms and it consists of two protein substances: fibroin and sericin and by 2-3% of fat and waxy materials, dyestuff and minerals. Silk is produced by silkworms, which secrete a long double and continuous filament (burr) that wraps around itself, forming the cocoon that is dipped in hot water to separate leaders and unravel it. In the spinning, the cocoon will join two or more filaments, the yarn thus obtained is twisted and put on the reel: this way we get raw silk. It can be white, yellowish, greenish or reddish. The dyeability of silk is similar to that of wool: it is dyed with basic dyestuff, acids, directs, premetallised dyes, vat dyes. The knitted fabrics of silk and those mixed with viscose and/or cotton are manufactured with circular machines, and they are usually finished with chemicals determined by purpose and use. Generally there are combinations of finishing based on silicone emulsions and resins to enhance stability, resistance to use and final appearance, etc. To complete these treatments there are mechanical finishing processes such as Sanfor rubber belt with slight compression.