The BBT-59.3 features integrated threads for full compatibility with the Park Tool BBT-RS Bottom Bracket Tool Retaining System (sold separately). The BBT-RS uses an adjustable spring-based tension system to apply consistent, adjustable pressure to the tool, ensuring full engagement with the tool fitting and preventing slippage.

Fits 16-notch threaded bottom bracket tool fittings with a major diameter (outside of notches) of 41–42 mm and a minor diameter (inside of notches) of 39 mm, including:
Shimano® Ultegra® BBR60
Shimano® Deore XT® MT-800
3/8″ drive fitting