Food grade silicone O rings -211, 2 for $1 shipped to the 48 states.
These are the ones that fit over 1/2" male NPT fitting in a weldless fitting. ID 13/16", CS 1/8", OD 1-1/16". I got them from McMaster Carr, catalogue #9396K32. I am told they also serve as food grade gaskets for 1/2" female camlock fittings.
Just getting rid of a few spares, hope it helps someone.
Edit: all gone.