PJP Double Jacket Flexible PVC Wire 10m/100m Spools - PJP 9012/spool/10N, Flexible double PVC jacketed wires, where the inner jacket is white which allows you to check the state of the wire insulator, if inner jacket is visible then wire is worn and it has to be replaced.
PJP 9012/spool/10N Black 3.
8mm Double Jacket Flexible PVC Wire 10M Spool