14 gauge. Choose from 5/8", 3/4", 7/8", 1", 1 & 3/16", 1 & 3/8" or 1 & 5/8". PTFE, polytetrafluoroethylene, is a flexible, nickel free wire. It can be autoclaved up to 230 °C (446 °F). Non toxic Allergy free Hospital Grade Flexible Cut to any Length if needed! These are very discreet and very comfortable