The Shimano SD300 Di2 Electric Wire is compatible with Shimano Di2 E-Tube drivetrain systems and is intended for use with internally routed frame setups.
More compact design makes new electric components smaller and lighter
Will potentially expand the future capabilities of DI2 systems
For internal routing usage (wire holder included)
Shimano Part Number: EW-SD300-I
Compatible System: Shimano E-TUBE system
Time Trial: Yes