High Quality Factory SYWV75-5 Coaxial Cable. Coaxial cable is a kind of electric wire and signal transmission line, which is generally made of four layers of materials: the innermost part is a conductive copper wire, the outer part of the line is surrounded by a layer of plastic (used for insulator and dielectric), and the outer part of the insulator is a thin mesh conductor (generally copper or alloy), and the outer part of the conductor is the outermost insulating material as the outer skin.