For weeks I've been seeing people, kids and adults, wearing these necklaces with a pendant that looks like a USB memory stick or tiny powerbank, with an LED shining in the middle.

Today I happened to see one up close, with a brand name on it.

It's an "air purifier" with "negative ions" removing "99% of viruses in 20 minutes".

Wow, if only I had the lack of ethics to make a quick buck like that. I expect they have profit margins close to their claimed efficacy.