The PSC retainer valves are plastic, and as Jack Burgess reports, there can be some work (and money spent) in getting one's hands on them. I have purchased mine directly from PSC-piggy backed on a larger order (the $30 minimum was satisfied). I have also ordered them Caboose Hobbies and waited for them- but not long (they send a lot of orders to PSC). I keep a generous stash of them, and they serve along with much other stuff-in-waiting as a vis a tergo -kick in the "behind"- that I still have a lot of kits lined-up to soak them all up, and I am not buying green bananas.

Denny

Denny S. Anspach MD
Sacramento