Our copper jump rings are solid copper, not plated copper. It starts the color of a shiny new penny but will darken or turn green over time. To clean copper, tumble or use an ultrasonic cleaner. Copper cleaners and polish will work also.
Our jump rings follow the American Wire Gauge (AWG), also known as Brown and Sharpe (B&S). All sizes listed are inside diameter (I.D.), which corresponds to the size of the mandrel onto which the wire is wound. Use these I.D.'s as a guide not an absolute as springback can occur.
AWG Wire Measurements: