External Shimano Di2 E-TUBE Junction A for cockpit wiring, under-stem mounting, battery/adjustment status, and charging access SM-EW90-A — 3-Port Junction A Shimano SM-EW90-A is an external Di2 E-TUBE Junction A unit for the cockpit area. It mounts under the stem and provides three E-TUBE/SD50 ports plus a charging port for compatible Shimano Di2 systems. Use it to connect Di2 shifters to the main frame wiring while providing access to battery status, adjustment mode, E-TUBE connection, and gear-position functions. SM-EW90-B — 5-Port Junction A Shimano SM-EW90-B is the 5-port version of the external Di2 E-TUBE Junction A unit for cockpit-area wiring. It mounts under the stem and is intended for Di2 setups needing additional switch or accessory-shifter connections, such as TT/triathlon or multi-shifter configurations. It includes five E-TUBE/SD50 ports plus a charging port and supports battery status, adjustment mode, E-TUBE connection, and gear-position functions.
