Shim Di2,Internal Junctn Box,B Sm-Jc41,For Ew-Sd50,4 Port Di2 E-Tubes Junction Box Shimano Electdrive

E-Tube kits, batteries, adaptors and chargers sold separately-EW-SD50-Internal Frame-This is the Shimano Ultegra Di2 Internal Junction Box. This box is referred to as the junction box ''B'' on a Di2 build. The SM-JC41 is for use with internal wiring setups