It is the plastic retainer that holds the spring in place above the plunger.

I made a few parts by printing on a prototype machine. I haven't put any to use yet, so I don't know how they stand up. Do you want to be the first?

Put a WTB in the classifieds. You might be surprised.

Thanks, I think I found one.

isnt this one of those moments, as a man, you think to yourself....god, I wish I owned a lathe

?
I know that's what I think