Ultegra Di 2 series with electronic shifting is pro-proven as it is a direct trickle down from our Dura Ace group. It stands for state-of-the-art technology, proven in pro races. The technologies used in the new Ultegra 6870 series 11 speed mean the electronic shifting does the work & lets you concentrate on your performance. ULTEGRA Front Derailleur with automatic trim function are offered to suit all cranks. ULTEGRA features Wide Link design, short & long cage Rear Derailleurs for precise & reliable shifting. Dual Control Levers with new ergonomic design for long rides & fast accurate electronic shifting. Buying a gearset is perfect for anyone wanting to upgrade their current drivetrain to electronic shifting. This version is specifically for bicycles capable of having an internal battery & cables. Charging is done via USB