As indicated in the brief Class Heading, yarns and threads, whether natural or synthetic, are in Class 23 so long as they are for textile use. Clearly, cotton, silk or woollen threads and yarns are in this class. Moreover, when used for textile purposes, fibreglass, elastic, rubber and plastic threads or yarns are also in Class 23. The same goods when not for textile use would be classified according to material composition in Cl. 21 (fiberglass threads) or Cl. 17 (elastic, rubber or plastic threads). And while raw silk, raw cotton and raw wool would belong to Cl. 22, spun silk, spun cotton and spun wool are in Class 23.
Thread of metal is also in Class 23 when it is used for embroidery, whereas thread of metal for binding is in Cl. 6 according to material composition and threads of precious metal being jewellery are in Cl. 14 as that is the appropriate class for jewellery items.
It should be noted that the Alphabetical List contains a number of threads that are classified in classes other than Class 23 due to their specialized uses. Some examples of these are threads of plastic for soldering in Cl. 17, surgical thread in Cl. 10 and identification threads for electric wires in Cl. 9.