ESD Return Spring
The ESD Return Spring replacement is a return spring for a vertical coin slide.
The spring helps the coin slide return back to its home position after a coin has been inserted into the coin mechanism.
If your mechanism is not returning properly, it is most likely that there is an issue with the springs and they should be replaced.
Best to get multiple of these as a vertical coin mechanism will sometimes have two springs on them. Games For Fun sells these springs in packs of 2, 4, and 12.