Have always wanted one of these cute antique mercury vapor bulbs. It has been used before, but seems to work very well at full power, and also seems very tolerant of running at reduced power, such as applying 120V to the 277 tap of a 100 watt metal halide ballast.
The color-correction coating is much thinner than any of my other lamps, yet somehow it works just as well. Package is in good shape, not dirty, not falling apart even though I believe these lamps to be 40-50 years old?
If I were to nit pick, the label on the top of the bulb is worn away, it is not as good as the one in the picture. But it is still readable, no big deal.