Park Tool Bottom Bracket & Crank Arm Tool BBT9 (Hollowtech II) A highly durable tool to remove & install Shimano Hollow Tech II integrated Bottom brackets & chainsets. The 16 precision, laser cut splines securely engage the notches of the bottom bracket cups, while the other end fits the 8 internal splines of the crank arm adjustment cap.A plastic coated handle gives a secure & comfortable grip & is long enough to offer plenty of leverage, so be careful not to overtighten when installing.