The Shimano BB-R9100 bottom bracket was specially designed for Dura Ace 11-speed cranks. It has small ball bearings to minimize weight and works with Hollowtech II technology for more stability and rotation efficiency. BB-R9100 is available in a version for BSA and for ITA threads.
Small ball bearings for low weight
Recommended for Dura Ace FC-R9100, FC-R9100-P, FC-9000