Presenting Shimano's new Ultegra Di2 6870 group set. The Ultegra series is Shimano's performance proven electronic group as it is a direct trickle down from Shimano's Dura Ace group. Following the Dura Ace's move to 11 speed and then to Electronic (Di2), Shimano has introduced both to the Ultegra.
Upgrade kit includes everything needed to move from a current 11 speed mechanical drivetrain to an electronic one- front and rear derailleurs, shifters, battery, charger and all the cables and wire harnesses.
The default configuration settings are for an external battery. If you need an internal battery there will be an upcharge.
Note: if your bars are 44cm or wider, the standard 350mm wires will be quite tight, and you may want to step up to 400mm