SUMMARY: They don’t work. Don’t waste your money!
I just pulled down the last one of these that I had up. I had bought a bunch of these things, and placed them is places where I had mouse activity. The mouse activity didn’t change at all. The brand I had was Weitech, but I am guessing they all work the same, which is not at all. Don’t waste your money.
The Federal Trade Commision (FTC) is even going after these guys: