Shimano SM-JC41 Di2 Internal Junction B Box Groupe Carbon fiber is the ideal

Carbon fiber is the ideal material for a gravity bar because fiber orientation and bar shape can be controlled independently and developed in unison

accurate front shifts

thanks to the matching dimensions and complete compatibility with wheels and frames

One piece alloy body design

The Thomson Masterpiece seatpost has a clamp

Shimano SM-JC41 Di2 Internal Junction B Box Groupe Carbon fiber is the idealFor internal DI2 wire routing, SHIMANO's SM JC41 Junction B is the central connector for DI2 systems. Wires from the front and rear derailleurs, cockpit area, and battery all plug into the 4 port SM JC41 junction, which is housed inside the bike frame. Specifications For internal wire routing Mfr Claimed Weight 4. 1g