You'll fall in love with beautiful and easy-to-use chain maille supplies by Weave Got Maille - including these 20-gauge jump rings with a 4mm I.D. (inner diameter) and 5.6mm O.D. (outer diameter). They are the larger diameter of the two 20-gauge enameled copper rings we carry and they come in a large selection of gorgeous hues. Made in the USA, these copper jump rings are coated with an enamel finish that's more reliable than anodized colors. Colors are tumble polished for a bright and shiny look. Sizes follow the American Wire Gauge (AWG) system of measurement.