The Vacuum Tube illustrates Moore’s Law by packing modern flash storage into a vacuum tube’s glass envelope.
Vacuum tubes are the primary reason that computers used to be room- or even building-sized affairs. Then the transistor and integrated circuit made miniaturization possible. A USB flash drive contains the equivalent of millions of vacuum tubes, so jamming one into the carcass of one of its previous constituents seemed perverse enough to be worthwhile.
It’s fully functional, but don’t put it in your pocket.