SHIMANO Di2 EW-90A 3-Port Connector Box

Ce connection box is the heart of every transmission SHIMANO Di2 Dura-Ace 9070, Ultegra 6870 and XTR. It's where shift commands and settings are stored. This will find its place under the stem.
 
It's a real computer, the brain of the system, and therefore an indispensable part: we offer it to you in the event of breakage or failure, so you can enjoy your transmission without buying the whole system!
 
It features a battery charge indicator and three ports (standard model).
 

Ref: 7970330116262