Saber Tactical Extended Female Quick Disconnect... washers?
So what and where are these washers intended to be used? Not obvious but I'm oblivious.
The large washer with the rubber is a Dowty seal. It is required to seal the parallel (BSPP) threads on the adapter. I'm not sure what the smaller o ring is for.
that is where i would ask your question
@marflow, I believe the white one goes on the bottom of the brass threads. In the hole of the connection and the brass threads bottom tight into it. I don't know the name of it, but I know without it , you'll have a high pressure leak. You'll find these on the bottom of air gauges also