-The open design allows you to confirm full engagement of the cup notches (unlike a centered socket tool, which is "blind.")

-The wrench is reversible to account for differences in cup notches--some notches are shallow and towards the front, others cut far into the cup. The reversible design allows you to select the position that gets the best "bite" on the cups, and also centers the wrench to prevent slippage.

-Unlike a stamped steel wrench, our "crow's foot" design allows the use of a torque wrench (simply snap onto the torque wrench at a 90 degree angle to the handle).

This particular wrench is very specific in its scope--it is only for the following Shimano Hollowtech II bottom brackets with reduced outside diameter bearing cups:

-Shimano Dura Ace (SM-BB9000)
-Shimano XTR (SM-BB93)

Does NOT fit the following "mini-cups":

-Shimano 105 (SM-BBR60)
-Shimano XT (BB-MT800)