Small antiqued copper plated brass ball chain clasps, for use with 1.8mm, 2.1mm, and 2.4mm ball chain. Antiqued copper plate is a copper plating that has been darkened to provide a "distressed" (oxidized) appearance. 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 clasps hook both ends of the chain together, to make a necklace or a key ring. If the clasp appears too tight to fit on your chain, gently loosen the clasp with an awl or chain-nose pliers.