The shimano dura ace di2 dual integrated intelligence is the next generation of junction boxes put to the test in competition and used in victories by pro riders in every condition including the 2012 tour de france team sky the under stem junction box a is versatile with the multiple shifters mount the junction box a under the stem with the included rubber harness and can be used with the 9070 setup with multiple shifters the ew90 a 3 port junction box is designed for a standard drop han