SHIMANO Cassette Sprocket, CS-R9100, DURA-ACE, 11-Speed, 11-12-13-14-15-17-19-21-23-25-28
- Cog Sizes: 11 - 25t, 11 - 28t, 11 - 30t, 12 - 25t, 12 - 28t.
- Cog Material: [five largest cogs] titanium, [six smallest cogs] nickel-plated Cro-Moly.
- Claimed Weight: [11-25t] 6.2oz (175g), [11-30t] 7.4oz (211g).