Shimano EW-AD305 SD300/SD50 Conversion Adapter

Shimano Di2 e-tube wire for electronic-shifting installs — the harness that carries power and signal between battery, junction, shifters and derailleurs. Length selection is the one fitment variable that matters for a clean install; longer runs loop around inside the frame, shorter runs tension between junctions. This is the Shimano EW-AD305 SD300/SD50 Conversion Adapter.