Park Tool Backrest STL-3K - for STL-1 Stool

The STL-3K is kit that will add a back rest to the STL-1.2 work stool. The STL-3K includes a back rest, two steel support bars, and fasteners.
NOTE: The STl-3K will only work on the STL-1.2 work stool. The previous STL-1 work stools will not accept the STL-3K