You may have already seen this article: https://www.advancedaquarist.com/2009/4/aafeature2
Sorry, I don't have any personal experience with them and share your caution. Sure there are some substantiated recommendations on this blog
Good pic! I have these in my QT and was concerned, but they are so tiny I couldn’t get a good enough pic to send in for ID. I was just going to describe them as shaped like little Star Trek com badges. Lol