Shimano Ultegra Di2 Grommets $4.99
Hide those wires.
If you have internal routing, you can cleanly run your Ultegra Di2 wires with these rubber Grommets. They come in packs of four and are available in a 6mm round profile or a 7 x 8mm oval profile to match most frame's internal openings.
Confused about how to build your Di2 Kit? Read our Learn Article.