Shimano Ultegra FC-R8000 1x Crankset FC-R8000 Ultegra Crankset customized for 1x with a Wolf Tooth Drop Stop 42T Round Chainring 172.5 mm arms Wolf Tooth Chainring is compatible with all 9/10/11 Speed Chains and many 12 Speed Chains but not all. This crank uses Shimano's commonly found Hollowtech II bottom brackets (not included). All necessary hardware is included. Condition is used. Clean and totally functional. Some scratches and heal rub to the driveside (see pictures). Non-driveside is nearly new since I used a different powermeter non-drive arm most of the time. Chainring has lots of life left.