Originally Posted by Andy M.
I give up, I ran out of Google images.
I've hit page 47 quite a few times myself
This item is the latest and greatest. They've only been around since the early nineties, but there are predecessors to this model that were around longer. Not nearly as reliable and not working on the same principle either, which also made them not as trustworthy.
There are instruments/objects out there that can sense individually what this item can sense both of, and people do
look at those, but they do not perform my particular item's function. Those items do
have "meter" in their names.