Editing Ski binding (section)

=== Nordic Norm (NN) ===
The incorporation of flexible plastics into ski boot soles allowed them to be strong torsionally and side-to-side, while retaining lengthwise flexibility and allowing the heel to rise as without the need for a cable about the heel. The Rottefella binding became standardized as the 75-mm, three-pin, Nordic Norm binding,<ref name=":0" />  which was widespread by the 1970s.<ref name="rot">[http://www.rottefella.no/en/Our-history/ "About Us"] {{webarchive|url=https://web.archive.org/web/20150906104003/http://www.rottefella.no/en/Our-history/|date=2015-09-06}}, Rottefella</ref>