If they just could bring out four terminals in the base, it could be a truly “universal/international” version, usable in 100- or 200-volt service—sort of...as series/parallel connected? :-)
You'd actually need only three terminals do to this. A lot of miniature vacuum tubes (e.g. 12AX7/ECC83 etc.) had such an arrangement for their filaments, enabling them to be wired for 6.3 or 12.6-volt operation.
