Shimano EW-SD50 Di2 E-Tube Wire 850mm. Shimano E-Tube wires and connectors
Frame grommets for E-tube internal-wiring compatible frames are sold separately see Shimano Frame Grommet Kit Electronic Shifter Extra Parts
Ultegra Di2 wires utilize Shimanos e-tube technology; e-tube is a two-prong system and is NOT cross compatible with Dura-Ace 7970 Di2 wiring
All e-tube wires may be used for internal or external applications