cover kit for external frame mounting of Di2 wire systems. If you don't have a frame with internal wiring setup for Di2, then you go with plan-B, external wiring. Of course protecting ...
This is the Shimano Ultegra Di2 External Junction ...
Box for connecting the two derailleurs, battery, and cockpit controls in a Shimano Di2 electronic shifting system. This junction works with all Di2 with e-tube wired system components as long as firmware ...