Copper inside, Some sort of plastic outside, plug at one end for insertion into wall socket, something at the other end to connect it to your thing there. Always insist on made in Québec electricity, much purer produced with colder water which does not cause thermic strain on turbines and run through colder wire (much better in winter) so requires less rectification. French electrons are also larger. You should also try to have all your equipment in line with the magnetic pole and, if at all possible, moving next to the dam with the shortest wire run is absolutely the best. My next subject will be on why, according to rubber garden-hose theory, large diameter speaker wire produces better bass. compared to thin wire