This is interesting. The connector definitely looks like those used in the original UE super.fi, triple.fi models as well as FLC8S (Forrest used to work for ue). FLC8S uses 0.75mm spacing just like UE 2pin connectors (and if I'm not mistaken in UERM and UERR monitors). The standard 2pin used by 64 audio, Noble, CustomArt, Unique Melody and others has 0.78mm spacing. Since you can easily fit U6, but not flc8, I would assume the spacing is 0.78mm, but the connector housing is typical of UE connectors. Strange, right?