Set of two largest cog units for Shimano Dura Ace 9000 / 9100 series 11-speed cassettes.

The double is 28 & 25T, and the three cogs are 23-21-19T.

The 3 cog unit is the more recent type with double rivets at each point to secure the cogs.

An earlier version only had one rivet at each point that tended to break off.

Nice clean condition.