Shimano E-Tube EW90 Di2 Junction A Box The Shimano SM-EW90 junction box connects via EW-SD50 wires to different points on your bicycle. Also used with Shimano SM-BCR2 battery charger to charge the SM-BTR2 without removing internal battery. 3-port design – one for downtube wire to bottom bracket junction, two for shifter connection 5-port design – one for downtube wire to bottom bracket junction, 4 for shifter connection allowing the addition of TT shifters. Battery level indicator feature E-tube EW-SD50 wires not included Additional charging point when using internal battery Gear index setup switch to allow fine tuning via shifter buttons Reliable and secure water resistant connectors Stem mounting strap included