The basis for the Coppertone RCA Interconnect is a very simple but very effective form: a tin-plated copper shield, helically wound around a thin-walled Teflon tube.
The jacket is a multifilament nylon yarn, while the conductor is a pure copper solid-core element that is formed into a “nami” (wave) shape in order to ensure that it is substantially suspended in the air dielectric within the Teflon tube. This “air suspension” allows for quite low capacitance and quite high velocity.
The RCA connector is a REAN NYS352G (made by Neutrik), utilizing gold-plated brass contacts – fairly common metallurgy at this level, and in the Copperzone interconnect it has nothing to apologise for.