Shimano Ultegra CS-6700 cassette 10 vitesses

Sprocket teeth combinations:

11-23: 11-12-13-14-15-16-17-19-21-23 T.
11-25: 11-12-13-14-15-17-19-21-23-25 T.
11-28: 11-12-13-14-15-17-19-21-24-28 T.
12-23: 12-13-14-15-16-17-18-19-21-23 T.
12-25: 12-13-14-15-16-17-19-21-23-25 T.

12-30 only compapatible with RD-6700A

Rapid gear shifting is achievable using components that have been designed to be used with one another. The cassette is an important element in the drivetrain. This is why the sprocket design has been optimized to allow you to get the most out of the Di2 system.