Save your money. These things have been around since I was a kid (long, long time ago). The only thing new about them is their circuitry and names.
If these things worked on cars, you'd see them as standard equipment on many if not all cars.
Virtually every time you see their sales gimick, it has something to do with ships using them. I don't know the physics of it but supposedly they work on ships because they are submersed in salt water 100% of the time but your car isn't.
