Di2 Electronic Shifting Quick and smooth front shifting under high pedaling torque Programmed control of chain guide SHIMANO Synchronized shift Full and semi synchronized shifting program Redesigned to fit wider gear pitch without sacrificing shifting Shorter length of rear center (410mm) with O.L.D. 135mm System communication with rear derailleur, Programmed control of chainguide works for minimal chance of chain drop Front Derailleur Clamp: Braze-on Speeds: 2 x 11 Top Gear Teeth: 46-53T Chain Stay Angle: 61-66 Chain Line: 43.5 Weight: 132g.