The Shimano EW-SD50-I E-Tube wire holder clips to an E-Tube wire and prevent the wire from moving or rattling inside the frame on an internally wired setup. The flexible ends are supple enough for easy wire installation into the frame, yet do an excellent job of suspending the wire and preventing movement. The wire holders are reusable. Spacing of the holders is your choice and largely defined by the length of runs, the challenges- such as small internal tube measurements or corners, as well as the internal diameter of the tubes. Our best tip is that in general you will want to use more, not less.