Di2 Electric Wire Cover
The Shimano Di2 wire cover sheath is a set of self-adhesive wire covers. They allow you to easily and cleanly route electric wires outside your frame. It also protects E-TUBE wires from wear and tear. The set includes 300 mm and 50 mm self-adhesive strips that stick gently to the bike frame for a clean look.
These covers are available in both black and white, to best match your frame.
Make sure your frame is real clean, peel off the tape on the back, route the Di2 electric wire through it and stick it on your frame. They don't always stick that well, but when they do they'll stay on forever.