Where the wires converge.
The E-Tube Di2 Junction Box is what is referred to as the B Junction. This is the point in the wiring system where all the component pieces converge. It's a crucial item along with the five required wire sections to operate your Ultegra 6770, Ultegra 6870, or Dura-Ace 9070 Di2 shift system.
The E-Tube Di2 Junction Box is available in two configurations—Internal (SM-JC41) and External (SM-JC40). The Internal style is designed to be located inside the bike frame (usually inside the down tube, tucked in from a hollow bottom bracket shell). The External version is designed to be fixed on the outside of the bottom bracket shell, usually fastened to the cable guide.
- Connects Di2 cycling component and battery wires
- Available in external or internal configurations
- Shimano's Di2 is the most popular electronic drivetrain in the pro ranks
- Item #SHI0394
- Crankset Compatibility
- 2 x 10
- Compatible Components
- Shimano Ultegra Di2
- Recommended Use
- ditching your mechanical tethers
- Manufacturer Warranty
- 2 years
What do you think about this product?
ViewSelecting an option will reload the available reviews on the page
Sorry, we don’t currently have any of those types of reviews for this product.
Need Expert Advice?
Our Gearheads Can Help
Cancer and Reproductive Harm - P65Warnings.ca.gov