This part (also known as a star-fangled nut) is used to set the preload adjustment on threadless headsets, in tandem with a top cap (not included). Proper installation requires the use of a star nut setter, a separately sold tool.
Please note that this item may not be suitable for use with some forks, including those with carbon fiber steerer tubes, which may require the use of an expanding bolt instead of a hammered-in star nut. Consult your fork manufacturer for more information.
