I use D.U.C.C Wire as a RCA Interconnect and Coax Cable.
It is my preferred wire to be used as the signal path in a Coax Cable.
I use PC Triple C Wire as present in Power Cables, again this does make a noticeable change to other Cables used, and makes a change for the better to Digital Sources. I will one day give D.U.C.C Wire a go as a Power Cable.
7n is a very soft and high purity wire.