Where to get an anti-torsion rope?

[Brezzin]

I've decided to ditch the sock for my Asymmetrical spinnaker in favor of a karver KFS furler. Most of the time it's just my wife and I sailing and because the Asym is 1400 sq ft, we won't fly it because as nice as the sock works, it can and does get away form you sometimes. I need something safer and furlable from the cockpit.
Defender has a nice price on the KF2 furler but it's without the anti-torsion line. Does anybody have a source for this line?

[tommays]

Seems like that would be something spliced to size for your boat and compatible with the sail you want to furl ?

For example i have and older sail with a built in wire luff that would work with that type of unit