Shimano

JC41 Di2 Internal Frame Junction Box 4-Port

Made exclusively for Ultegra 6770-Di2 electronic shifting systems. The junction box is what ties the whole system together. 

• Each bike will need cockpit area cable SM-EW67 and the following from the junction box: (1) to front derailleur, (1) to battery, (1) to rear derailleur, and (1) to cockpit area. (Please consult Shimano.com for proper measuring information) 
• 4 connector junction box for internal cable frames. 
• Because some frame manufacturers use custom junction boxes for their frames please consult with them before installation.
• 7970-Di2 and 6770-Di2 cables are not compatible