A cable clip to supplement the measly 5 you get if you buy the routing kit or happen to break one or 3 of them.  Printed in Prusament PETG, it mounts nicely with an M3 or M4 screw.  The screw hole is 4mm, but I've included the blender file if you want to change that.  I used the Blender Addon CADSketcher for this and the Cable Guide, highly recommend it.