10cm of single coil latex tubing for the mounting of single coil pickups. Enough to mount a whole set of pickups.
Regularly used in the mounting of most Fender style pickups, as was used in the earliest days of the guitars' manufacture, tubing was cut down to size and slipped on to the thread of the mounting screws. It was compressed as the pickups were screwed onto the guitar's hardware, providing a force to enable different pickup heights. This has been mostly replaced by springs in modern times, but many still prefer tubing for vintage accuracy, or the feel when adjusting the height of pickups.