Flex-Floss comes in a hank about 8 inches long with 100+ pieces. It is used for bodies or as legs on many flies. Its relatively thin, strong , light and can be stretched. The big advantage it that is resists rot unlike normal rubber. We use it on our chironomids, emergers, and as a rib on adult stoneflies.. A great tying material.
Daddy Long Legs mini-Flex Floss