Shimano Shimano Di2 E-Tube 4 Port Junction B - (SM-JC40 or SM-JC41) Bike-Electronics-Mounts & Sensors-Phone Mounts Also supports the Touring

Also supports the Touring

CO2 Holder

RPM Cadence Sensor

8mm diameter handlebars

In-Mold Construction fuses a tough polycarbonate outer shell with the helmet's impact-absorbing foam liner

Shimano Shimano Di2 E-Tube 4 Port Junction B - (SM-JC40 or SM-JC41) Bike-Electronics-Mounts & Sensors-Phone Mounts Also supports the TouringThe Shimano Di2 Junction B box is the center of the e tube Di2 system. All of the component and battery wires meet here before running out to their respective components. All of the wires that connect to the junction box use the same connector to make assembly that much easier. Choose the SM JC40 External box if you are running your wires on the exterior of the frame or choose the SM JC41 internal box if you are running your wires inside your frame.