This box has thirteen orange digits at the top, which look like Nixie tubes. But they are a different technology called edge-lit lightguide display. Each digit has ten plastic sheets and ten lightbulbs. Each sheet has dots etched in the shape of a number. Lighting a sheet lights up that number.

@kenshirriff I definitely thought those were nixies from the look and age. Are the bulbs neon, or is it just very warm incandescent?