Please note, these cables are:
1) for internal routing use only 
2) compatible with Shimano R9200, R8100, R7100 Di2 series (12 speed) only.

SHIMANO Built-In Type Di2 Battery [SD300 Type]
BT-DN300
The new DN300 battery features the same waterproof design that Di2 users have loved for generations. Now with 3 ports, it delivers stable power to Shimano's 12-speed road derailleurs and shifters (if a fully wired option is selected).

With the same size as its predecessor, the slim DN300 battery can be housed inside seat posts or frames ensuring a clean aesthetic. Now with 3 ports, the DN300 simplifies wiring to front and rear derailleurs, supplying stable power at all times. The third port is for riders who seek the redundancy of Shimano's 12-speed Di2 wired option.

FEATURES
Compatible with thinner next generation electric wire SD300 and systems after R9250/R8150 series
3 SD300 ports
Shared fixing method with BT-DN110

PRODUCT SPECIFICATIONS
MODEL NO: BT-DN300
SERIES: DURA-ACE R9200 Series
Average weight: 52
Type: Built-in battery
Compatible charger: RD-R9250, RD-R8150, RD-R7150 (NEW)
Firmware update by E-TUBE PROJECT: ✔
Master unit: ✔
Chemistry: Li-Ion
Rated capacity (Ah): 0.5
Rated capacity (Wh): 3.7
Rated voltage (V): 7.4
SD300 connector (pcs): 0
SD300 port (pcs): 3
SD50 connector (pcs): 0
SD50 port (pcs): 0