This is Park's shop-quality tool for installing your Shimano 10-speed Hollowtech II bottom bracket cups. It's long enough to give you adequate leverage for installing the cups with the force you need. The precisely shaped metal teeth of the BBT-9 won't damage the teeth on your BB cups provided you use it with care. The small end of the BBT-9 has what looks like a plastic wheel on it. This is actually, the splined plastic tool that you'll need for the spindle bolt to preload the bearings on your Hollowtech crankset. Otherwise, the Park Tool BBT-9 is compatible with Shimano Hollowtech II, FSA Mega Exo, SRAM GXP, and most other external bearing bottom bracket cups.