Four carbon carriers and six titanium cogs for reduced weight Nickel-plated finish for corrosion and wear resistance Dyna-Sys11 cassette with Rhythm step gearing for closer gear ratios and smoother shifting performance Fits Dyna-sys11 and current Shimano 9/10-Speed MTB hubs The largest cog (40t) is positioned inboard and above the drive-side flange. hubs with tall drive-side flanges may not be compatible due to spoke interference