Never miss a shift again with the fast, reliable Shimano Ultegra Di2 electronic drivetrain;Adjustable Top Tube IsoSpeed lets you adjust compliance to your preference, and it’s damped with an elastomer so it rebounds in a smooth, controlled, stable motion;All the aero advantages of Madone, plus the added capability to clip on aero bars for triathlons and time trials;Disc brakes offer better braking performance and extra clearance for wider, more stable tyres;