Shimano Dura-Ace Di2 Hydraulic Disc Brake option for road. The R9170 brake lever integrates the hydraulics in the shifter and the flat mount brake calliper is as lightweight and aerodynamic as you would expect from Dura-Ace. The 11-speed shifters can provide multi-shifting, which can be toggled on and off. The Dual Control lever has greater grip and greater fine tuning ergonomics. With the better positive feedback you get more in tune with your shift. Not to mention the lack of stretch or corrosion. A new feature of Dura-Ace Di2 is the option to use Shimano’s synchronised shifting technology. Perfected on Shimano’s XTR and XT mountain bike ranges, this system can control both front and rear derailleurs via one shift lever using a pre-programmed map. There is also the option for the user to customize the shift map to their own preference.