Shimano Dura-Ace RD-R9250 Di2 Rear Derailleur

Shimano's flagship component group, the 9200-level Dura Ace is further refined, faster and smoother. The rear derailleur covers a 11-34t range cassette and Shimano claims it to be 58% faster than the 9150. The compact design includes an integrated wireless unit, charger, and switch, and this derailleur also of course uses Shimano's E-Tube wiring system.