BOTTOM BRACKET PARK BBT-59.3 16-NOTCHx41mm f/SHI BBR60A precision CNC machined aluminum tool for the installation and removal of select threaded bottom brackets with 16 notch tool fittings, including Shimano Ultegra BBR60 and Deore XT MT 800 bottom brackets The BBT 59. 3 features integrated threads for full compatibility with the Park Tool BBT RS Bottom Bracket Tool Retaining System (sold separately) Fits 16 notch threaded bottom bracket tool fittings with a major diameter (outside of notches) of 4142 mm