I have several of these power cords. The outer woven sleeve is cosmetic only. It slipped on one end and the rubber like cable insulation is labeled "Furukawa Super Pure Copper Multi Conductor". Furukawa appears to be a massive Japanese company spanning multi-industries.
It has been a long time since using them on my mono amps. In my system on the monos they seemed to add a bit of a veil, so I have them doing subwoofer duty.