Shimano SM-JC41 Di2 Internal Junction B Box Groupe thanks to the matching dimensions

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

One piece alloy body design

and upper tube strong enough to withstand 325 foot-lbs of torque

The Thomson Masterpiece seatpost has a clamp

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

Shimano SM-JC41 Di2 Internal Junction B Box Groupe thanks to the matching dimensionsFor 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