I’ll let pictures do as much of the talking as possible. Shimano 105 Di2 Hydraulic Disc Brake Dual Control Levers (2×12-speed) – Left (front derailleur/brake) and Right (rear derailleur/brake) ...
With the new Ultegra RX derailleur, Shimano expands compatibility to mechanical road shifting and suggests there is a benefit in having a clutch rear derailleur with double front chain rings ... as ...