<!--ProdInc[300200816]/Mall:[backcountry_US]-->Shimano’s E-Tube Di2 Junction Box (also known as the B junction) connects all your component and battery wires to make assembly much easier. 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). <h3>Details</h3> 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 <h3>Tech Specs</h3> Crankset Compatibility : 2 x 10 Compatible Components : Shimano Ultegra Di2 Recommended Use : ditching your mechanical tethers Manufacturer Warranty : 2 years