Shimano's new SD300 electric wire cables for 12-speed Di2 groupsets. 

The new system only requires two cables now, feeding from the internal battery (typically installed in the seatpost), directly into the front and rear derailleurs. 

Length Guide
Front Derailleur to Internal Battery: 750mm
Rear Derailleur to Internal Battery: 1200mm

Please note this guide is intended to be used as reference only. Required cable lengths will differ depending on setup and frame size.

Specifications
More compact design makes new electric components smaller and lighter
Will potentially expand the future capabilities of DI2 systems

Mfr Claimed Weight
TBC