About Park Tool Bottom Bracket Tool Shimano/ISIS 8-Notch (BBT-18)
The BBT-18 is a heavy duty, investment cast tool for installing and removing the following:

Shimano® Octalink® right side bottom bracket cup with external notches

Bontrager® ISIS Drive™ bottom bracket cups

Front chainring lockring for Bosch® Gen 3 and Gen 4 e-bike systems and Specialized® Levo® Brose® e-bike systems

Features
8 notches with an outside diameter of nominally 43.4mm

The inside-to-inside width is approximately 38mm

Each notch is approximately 3.9mm wide

The hole in the center of the casting is 22.5mm, and will not fit over 30mm spindles

Can be used with a 36mm crow foot (such as the TWB-36) or open-ended wrench

Fits
Truvativ® (Threaded): ISIS Drive and Giga Pipe™

About Park Tool
Park Tool are the world's largest bicycle tool manufacturer. Located in St. Paul Minnesota they have been designing and manufacturing bicycle specific tools since 1963. Their dedication to quality and innovation have gained them the reputation for producing the best bicycle tools in the world.