A Nixie tube, or cold cathode display, is an electronic device used for displaying numerals or other information using glow discharge. The glass tube contains a wire-mesh anode and multiple cathodes, shaped like numerals or other symbols. Applying power to one cathode surrounds it with an orange glow discharge.

Why are Nixie clocks so expensive?

Clocks and watches are so expensive not only because of the tubes but also because of the high voltage supply. Nixie clocks require extremely efficient components, and you have to pay for them, as well.

How long do Nixie clocks last?

Average longevity of Nixie tubes varied from about 5,000 hours for the earliest types, to as high as 200,000 hours or more for some of the last types to be introduced.