That’s a VFD not Nixie. Completely different technology at work there.
yes i know …
@Bunny_Evans In fact I wrote “nixie” on purpose in the title to maximize chances to be seen from people using nixie tubes. I know the nixies are fully different and much nicer but much more expensive than the VFDs 
@aeropic Ah.
I think the master of the VFD is Noritake, they also do excellent ceramic tableware.
The old water heater display was VFD, they do dim with age but it was still perfectly legible when it was replaced after 16~17 years. The new one is LCD/LED back light.
@Bunny_Evans I bought my tube from a russian seller o ebay, they are probably not that young as ther is written CCCP on the glass