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.

Features

Compatible with Shimano e-tube Di2 systems (not compatible with Dura Ace 7970)

For internal wiring setups only

Made in Japan

Shimano part number ISMJC41