Two part ferrule eh?
OK, I'm going to have to buy a vowel here...
Where exactly and attached to what did you you find this thing?
The two part ferrule sounded familiar, then I remembered a fitting used on the pilot light tube for a gas valve.
Not the same thing, but that still may mean a two part ferrule is meant to be used on fuel lines.
I doubt it was made to be used on PEX.
Maybe it was intended to be used on metal hydraulic lines or a fuel system of some kind like propane equipment maybe?
You could check with an auto parts store or a supply house that specializes in boiler equipment and hydraulics.
I have to admit, I'm not sure.
I wish I'd never looked at that picture now...
I'll be thinking about that crazy thing for the next week.
Thanks a lot.