Push pin retainers come in many various sizes, but basically all serve the same purpose. They are designed to secure panels together by pushing the retainer through both panels and then pushing the pin to expand the clip locking it tightly into the hole. Basically, if you need a retainer like this, measure the hole and then look for a push pin retainer that will fit that hole with a head appealing to your application and a stem length that will be long enough to do the job.
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