14kt Gold-filled. Outside diameter measures 6mm, made up of 18 gauge wire. Sold individually. Whether connecting a clasp to a chain or attaching a charm, jump rings are one of the most versatile findings available for jewelry making. The gauge, also known as the size of the wire, of the ring is choosen according to the durability needs of the design and the size of items being linked together. Heavy jump rings are made of 18 gauge while delicate designs often call for 22 gauge.