Shimano Dura-Ace RD-R9250 Di2 Rear Derailleur - 12-Speed Disc Brake Pads Combined with accurate built-in power

Combined with accurate built-in power measurement at +/- 1% and support for grades up to 20%

and anyone who regularly rides in traffic and wants an extra layer of situational awareness

The top-mounted digital gauge reads to plus or minus 1% accuracy in 0

this is it

Shimano Dura-Ace RD-R9250 Di2 Rear Derailleur - 12-Speed Disc Brake Pads Combined with accurate built-in powerWhy Is the Shimano Dura Ace RD R9250 the Fastest Rear Derailleur Shimano Makes? The Shimano Dura Ace RD R9250 is a complete ground up redesign that shifts 58% faster than the previous generation RD R9150, housed in a compact Shadow RD low profile body with a full carbon fiber cage that cuts weight without sacrificing rigidity. What sets the R9250 apart from all previous Di2 generations is the fully consolidated wireless hub built into the derailleur