For a Flexi Floss body, stretching adjusts the diameter of the material with each wrap. Maintain constant tension if you want even segments. For legs, secure a sufficiently long section, then even out both sides once the body is complete. Release the tension before cutting: the material’s length under tension is not the same as the length it will have on the fly. The 1-meter spool can be cut to size depending on the fly you’re tying.