EW-JC304
Brand: Shimano
Four-port E-Tube SD300 junction, the largest of the 12-speed Di2 generation. Inside the frame it gathers the wires from the front derailleur, rear derailleur, BT-DN300 battery and controls, on SD300 connectors that are markedly slimmer than SD50. It entered the Shimano catalogue with the SD300 generation in 2020.
| Type | Electronic shifting accessory |
|---|---|
| Model years | since 2020 |