20" 1.0mm sterling silver ball chain necklaces. Unlike most types of chain, ball chain does not contain any open links. Instead it’s made of metal spheres (balls) that are linked at regular intervals with connector bars. Ball chain is a trendy option for making simple custom necklaces that display personalized charms (like letter charms and symbol charms to express who you are). These necklaces are finished with a spring ring clasp.