Shimano EW-JC304 Di2 Junction Box - 4 Ports, Use With EW-SD300

The Shimano EW-JC304 SD300 Di2 Junction Box is a 4-port connector designed for integrating multiple Di2 components using EW-SD300 E-Tube wires. This junction box facilitates seamless communication between elements such as derailleurs, shifters, and batteries within Shimano's Di2 electronic shifting systems. Its compact design allows for discreet installation inside frame tubing, ensuring a clean and efficient setup.