About Fly Tying Thread 12/0 by Veevus:

This thread has an incredible breaking strength to size ratio, spins to cord or lays flat, whip finishes effortlessly and holds material very well.

The strength and stretch, is unbelievable for standard 100% polyester fly tying thread. This non-waxed thread has a "wavy" textured surface that "grabs and grips" materials locking them in with less wraps.

You will get more thread wraps on your tiny dries for increased strength, get less thread build up when tying-in multiple materials at the head of the fly.