S Number (wool)

S Number (wool)

An S number on the label of a wool suit, or other tailored wool apparel, indicates the fineness of the wool fiber used in the making of the apparel. The numbers may also be found on wool fabric and yarn. The S numbers for fine wool products are intended to state, with precision, the fineness of the wool fiber used in the product, as measured in micrometres. Fiber fineness is one of the factors determining the quality and performance of a wool product. In recent years it has also become an important marketing device used by many mills, garment makers, and retailers. The S numbers may be used on products of 100 percent wool as well as on blends of at least 45 percent wool. The S number appears as a plural with an " s " or " 's " following the number, such as 100s or 100's.