This 690-XXL tool is a facer for large headtubes. It has a nominal outside diameter of 65mm. Use this 690-XXL facer with #750 Centering Cone Adaptor and #789 Reamer or #790 Pilot when facing head tubes with 55.95 - 55.90mm I.D.
NOTE: Always use a cutting fluid such as Park Tool CF-2 when machining.
SHIS terminology: faces headtube faces up to the ZS56 or EC56
Manufacturer's Part Number: 690-XXL