This triple insulated litz wire has a single wire diameter of 0.08mm and consists of 1700 strands, all wrapped in ETFE insulation. But what exactly is ETFE insulation? What are its advantages? ETFE, or ethylene tetrafluoroethylene, is a fluoropolymer with excellent thermal, mechanical and chemical properties. Its high dielectric strength and ability to withstand harsh environments make it ideal for demanding applications.