SHIMANO Dura-Ace SM-JC41 Bult-In Type DI2 Junction B Internal Wire Routing 4-Port

SHIMANO SM-JC41 DI2 Internal Junction Box EW-SD50 Wires

SHIMANO Dura-Ace SM-JC41 Bult-In Type DI2 Junction B Internal Wire Routing 4-Port

This is the Shimano Ultegra Di2 Internal Junction Box. This box is referred to as the junction box "B" on a Di2 build. The SM-JC41 is for use with internal wiring setups and is the main center of e-tube Di2 systems. For external wiring setups see the SM-JC40.

Frame Junction Box connects via SD50 E-tube wires to four different points: front derailleur, rear derailleur, cockpit junction box, and battery mount 

Use the Di2 system checker to update component firmware from http://e-tubeproject.shimano.com/ 

All Di2 components on the bicycle require the same firmware version. Using Di2 components with different firmware versions may cause malfunctions

E-tube kits, batteries, adaptors, and chargers are sold separately

Description: For internal use only
Fits: EW-SD50
Model: SM-JC41
Mount: Internal Frame
Series: DI2
Type: Junction B, 4-Port
Weight: 4.1

Original Shimano parts guarantee that all components work perfectly for optimum performance and maximum safety and longevity.