The famous Lexus LX 96 strand high purity 6N copper litz speaker cable from Audio Note. Black outer sleeved containing 4 sleeved conductors, 2 red (send) and 2 white (return). Each conductor is made of 24 strands of copper - outer diameter 1.9mm, inner diameter 1.1mm. Outer diameter of whole cable is 6.8mm.
Litz is composed of very fine strands of high purity copper wire insulated from each other with a fine polyeurthane coating, then bundled to form a larger gauge wire. The varnish on each strand must be scrapped off before a good solder joint can be achieved. You can flatten the wire, then use a single edged razor blade held 85-90 degrees to "shave" the varnish off the wire. After removing most of the varnish, use a 40 watt solder iron and a bit of solder to burn off the rest. A scum will bubble up and harden after the wire cools off. A solder pot can also be used to burn the varnish off.
Sold in multiples of 1 metre (mono, enough for one speaker), supplied in one continous length.
PRICE, 1m length