The Shimano Di2 SM-JC41 internal junction box is where all roads meet in the e-tube version of the Shimano Di2 system.
All of the component and battery wires meet here before running out to their respective components - all of the wires that connect to the junction box use the same connector to make assembly that much easier.
This junction box is only made to be mounted internally on frames specially designed for an internally routed system.
For internal wiring setups only
Please Note:- E-tube is a two prong system and is NOT cross compatible with older Dura-Ace 7970 Di2 wiring.
