Assertion: crampon | /r/MadeOf | hardened steel
Facets:
value: usually
type: TEMPORAL
Source sentences:
text: Crampons are usually made of hardened steel, but lighter weight aluminum crampons came of age with the popularity of European alpine ski touring.
text: Crampons are usually made of hardened steel, but lighter weight aluminum crampons are popular for alpine ski touring where the need for them is less frequent & counterbalanced by the need for a light pack yielding fast, efficient travel over long distances.