Coaxial cable
Such cables are usually made of a conducting wire. Then there is some insulation, then there is another layer of conducting material. Finally there is the (insulating) mantle. Such cables are used as a high-frequency transmission line to carry a high-frequency or broadband signal. Because the electromagnetic field carrying the signal exists (ideally) only in the space between the inner and outer conductors, it cannot interfere with or suffer interference from external electromagnetic fields.