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Equipment > Components > Brake Levers > Electronic Supplies


Considered a B-junction in Di2 parlance, the Shimano e-Tube Di2 SM-JC41 Junction Box is the central connector for internally routed Di2 e-Tube systems. Wires from the front and rear derailleurs, cockpit area, and battery all plug into the 4-port SM-JC40 junction, which integrates the inputs for full connectivity. Remember that a single wire is run from the cockpit junction box down to the SM-JC41, as the cockpit junction A integrates the shifters.

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  • 4-port junction box for internally wired Di2 e-Tube set-ups; integrates the ported wires
  • Can connect e-Tube wires from: front and rear Di2 derailleurs, cockpit junction, battery
  • Sit inside lower downtube/BB area on most frame designs
  • Composite material; sealed
  • Color: Black
  • Weight: 5 grams
  • Shimano part # ISMJC41
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