"The new EC300 charging connector is designed specifically for Shimano's 12-speed Di2 road drivetrains. Connected via the rear derailleur, it is also compatible with Shimano power meters.
Charging of the new Shimano 12-speed Di2 road drivetrains is now accomplished with the EC300 charger cord. Attached to the rear derailleur, this new cord is less expensive than previous chargers and can also be used to charge Shimano power meters.
• Charging connector for RD-R9250 and FC-R9200-P
• Compatible with charging FC-R9200-P
• 1.5 m cable length