Medium 3.2mm raw copper ball chain clasps for jewelry making. Fits 3.2mm ball chain. 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. Copper is a malleable metal. If the clasp doesn't open easily, loosen it slightly with an awl or chain-nose pliers to reduce wear on the end ball.