Dual Leg Power Meter, pair with DuraAce or Ultegra Crank : https://www.pioneerelectronics.com/PUSA/Cycle+Sports/Power+Meters/SBT-PM9100C

This unit provides advanced pedal monitoring which is supported by Wahoo cycling computers. 

I contacted pioneer support and confirmed that they will install on: Shimano Ultegra FC-8100 or Dura-Ace FC-R9100! I have done this with several units and it’s super smooth , the kit has a box to ship the crank and they will install , calibrate and return.