Well my mind is totally bogled. I picked up two of these at Goodwill Outlet. One worked and one didn’t so I took it apart. It mostly snapped together with 3 hidden screws. It has a circuit board smaller than a WIFI card and a mercury lamp 4 inches long. The lamp has wires the same size as earphones. It gives off a royal blue light. The wavelenght is UV-C at 253.7 nm. They are still made. The newer models have USB power and a gravity switch so you can’t point it in your eyes. The weight is 2.2 oz without 4aaa batteries. This is lite enough to carry on a bicycle tour. But this is somewhat probematic with me since my clothes are Aramid which dosen’t like UV light. Handheld UVC Disinfection Sterilizer Lamp – Stiylo
Glue some UV pass filter over it and you’d have a very respectable low-cost mineral lamp.