Only, much of the time they don't actually seem to work. They remind me of those little fan-like gadgets people sell online that goes in your car air intake an

Only, much of the time they don't actually seem to work. They remind me of those little fan-like gadgets people sell online that goes in your car air intake and supposedly gives you more horsepower. I've always been amazed that there is enough of a market for things, that rather obviously do not work, for companies to actually bother making and selling these things.