This is the Shimano Ultegra CS-8000 11-Speed Cassette.
Using Hyperglide sprockets with revised tooth profiles,
the CS-8000 11-speed cassette features reduced wear and lightning quick shifts.
Even under the most demanding gear changes you can expect improved shifting thanks
to a rigid aluminum carrier to keep the cogs in check.
The available ratio combinations (seen below) work extremely well with standard,
compact or triple cranksets.
Features:
Close & wide-range gearing options
Nickel-plated steel cogs for corrosion resistance
HG-EV 11-Speed Cassette
Specifications:
Cassette Body Type: Shimano/SRAM 11 Speed Road
Drivetrain Speeds: 11
Options: 11-28/11-30/11-32T