A self-contained set for accurate facing of a Bottom bracket shell Simple to use tool which ensures the seating faces of a bottom bracket shell are parallel which is essential for the smooth running & long life of Bottom brackets especially Shimano Hollow Tech II Comes with threaded inserts to ensure the tool is in the perfect position for accurate facing A powerful spring keeps the cutter at the ideal pressure for a perfect job High quality cutting head is replaceable Use with plenty of cutting oil for a superior job