Nylon washer used in Stern ball shooter assemblies (Stranger Things to present).
This nylon washer is located between the shooter housing & the inner spring on the inside of the cabinet (see secondary photo for detail). The other two washers in this assembly are metal.
Substituting this nylon washer for the metal washer in pre-Godzilla shooter assemblies can resolve sticky shooter rod issues.
The nylon washer & the metal washer share the same Stern part number, which can be confusing.