Updated SM-BB51 Shimano SM-BB52 Deore Hollowtech Ii Bottom Bracket (68/73-mm Bsa) FC-M582/FC-M590/FC-M610/FC-M660/FC-M670/FC-M770/FC-M780/FC-M980 FC-M4050 FC-M4060 Labyrinth seals for durability in wet conditions Shimano Reference Number:SM-BB51 SM-BB52 Suitable for SHIMANO FSA RACEFACE. Suitable for SHIMANO DEORE SLX XT XTR . Suitable for tooth plate model:FC-M582/FC-M590/FC-M610/FC-M660/FC-M670/FC-M770/FC-M780/FC-M980 FC-M4050 FC-M4060