PETEREK
Member of the Trade: ThePETEREK on Etsy
Previously known as cCasper TFG
It's fairly flexible, definitely enough for a headphone cable. I prefer to use Mogami w2893 over it though, it's much more flexible. The canare is 4x24awg wires, and the Mogami is 4x26awg. Either is good though, both are very cheap and good quality.
I order from here: http://www.redco.com/Bulk-Quad-Microphone-Cable/
I order from here: http://www.redco.com/Bulk-Quad-Microphone-Cable/