This is the close-up of the Black Cat Cable AERON™ insulator. Notice the spaces between where the yarns interlock? Those are the inter-nodal gaps that trap air as part of the dielectric medium, and one of the reasons that AERON is an effective low-capacitance insulator! In this photo multifilament nylon from an American source is used as the yarn. In more advanced versions a continuous-filament raw-PTFE ("Teflon") yarn made by a Japanese company is implemented. Other materials are also possible for future projects (read: in the works!) ..