Spring plungers can be used for locating or for applying pressure, as a detent or for ejection.
Slotted on both ends for installation with a screwdriver. With a pin that is longer than a ball, these provide a large surface to handle side loads.

Spring plungers without thread coatings are for use in soft material such as aluminum, in extreme temperatures, and on parts requiring frequent assembly and removal.

Spring plungers with thread coatings have paint nylon glue to the threads adds friction to resist loosening from vibration.