Shimano DI2 Internal Junction Box (4 Ports)An essential element for connecting all Di2 Shimano cables in the frame. Shimano DI2 Internal Junction Box (4 Ports)The Shimano Di2 ISMJC41 junction box allows you to connect up to 4 wires inside the frame, usually placed on the bottom bracket.features

• - Compatible with Shimano ultégra 6870 and dura ace 9150
• - Reference: ISMJC41