Shimano Junction Box Di2 E-tube Ew-90a 3port

The Shimano Di2SM-EW90-A 3-Port Cockpit Junction Box connects Di2 shifters to the frame junction box via SD50 or Y-series e-Tube wires and is most commonly used for standard road bar set-ups where a handlebar end junction A is not an option. The 3-port Cockpit junction box does not allow for the multiple satellite shifting options like the 5-port version but it is a little lighter and sleeker. If you intend to use satellite shift buttons or have a full aerobar set-up you should choose the SM-EW90-B 5-port version. To mount under a stem you’ll need the SM-EW90 Di2 Junction Box Mount.