Simpson 460 that's the only portable multimeter using a fluorescent display I've ever seen. Custom silicon. For its 7-hour rated NiCd life what size are they?
In that era, there were many calculators using VFD's with PMOS IC's ok doing direct drive at the higher voltage. But the power drain was high.
edit: Simpson 460 review was
Feb. 1972 Popular Electronics but Archive.org is being a jerk requiring sign-out to read it. $395 in 1972 is around $2,800 in today's dollars. It weighs 6lbs, 0.1% basic DC.
The model seems to have come out in
1971 multimeter model listing, no idea of the VFD vs LED.
Bubble LED's were used in the Sinclair
PDM35 1975-ish. It's kinda cute.