UNI Nylon Stretch is a thick stretchy poly material that is ideal as a floss substitute and for making under bodies. It was an item used by Dick Talluer for many years. This tends to lay flat and will create smooth underbody to build up shapes. It is used to build scuds, stoneflies and saves working with loads of dubbing. Talluer used this instead of floss on things like Carrie Stevens patterns and New England streamers.