Shimano SM-JC40 External Junction Box
The Shimano E-Tube Di2 SM-JC40 External Junction Box goes underneath the bottom bracket and mounts where a cable guide is usually located. The included screw threads into the hole that is normally used for the cable guide mounting screw. The Junction box is aptly named as four Di2 E-Tube wires emanate from the Junction Box.
- 10 grams
- Includes mounting screws
- Attaches to bottom bracket cable guide mount