Building off the tried and true reliability and functionality of the 10 speed drivetrain, Shimano built the 6770 Di2 Groupset around maximum compatibility. With the ability to fit a 10 speed cassette on just about every freehub out there, this is the drivetrain of choice for those with a dedicated set of 10 or 9 speed wheels. The Ultegra series is Shimano's performance proven electronic group as it is a direct trickle down from Shimano's Dura Ace group.
Complete Group includes every piece of the Di2 Ultegra 6770 electronic drivetrain- crankset, cassette, chain, front and rear derailleurs, shifters, battery, charger and all the cables and wiring harnesses.
The default configuration settings are for an internal battery and internal wiring. Please make sure your frame has the capabilities to have the wires routed internally and if does not then be sure to select each of the external options.