We love the durable and easy-to-use chain maille supplies created by Weave Got Maille, and these 18-gauge jump rings with 5.5mm inner diameter (I.D.) and 7.6mm outer diameter (O.D.) are no exception. Made in the USA from copper wire, these chain maille findings are coated with brilliant enamel colors that are more reliable than anodized colors. Each color is tumble polished for a bright and shiny appearance. Jump ring sizes follow the American Wire Gauge (AWG) system of measurement (18-gauge is thicker than 20-gauge), and the inner diameter measurement corresponds to the size of the mandrel on which the jump rings were made.