The Shimano Dura-Ace BB-R9100 Bottom Bracket is system engineering at its peak. Each of the components magnifies the qualities of the others for an unparalleled level of performance. Optimizing input to maximize output. That's how it achieves supremacy. Note: Bottom bracket no longer includes plastic adapter tool. Must be purchased separately. Features: Bottom bracket with small ball bearings for extra weight savings Advanced seal construction for smoother rotation Specifications: Frame Interface: BSA/English Threaded Spindle Interface: 24mm (Shimano Hollowtech II, FSA MegaExo, Surly OD, FSA MegaExo Light, RaceFace EXI) Bottom Bracket Shell ID: 1.37 Shell Width: 68mm Color: Black Weight: 65.0g (Manufacturer Claimed)