First of all I really like that it's SUPER easy to install and that it's solar powered! However, you get what you pay for. However, I bought them to put on our trailer to monitor tire pressure and temperature during the 500 mile trip from Georgia to North Carolina. There are some pluses. As I said, it's solar powered with connectivity, it's super easy to install and it really works! The only scam I can think of, or rather know of, is that it's very difficult to read and set up. Your tires must be deflated when fitted and then deflated and it will show correctly. However, we didn't know anything about it until the middle of our trip. We aired our trailer's tires, then turned on the surveillance system, and whatever it showed, we left. But he always followed closely. We set all (4) alarms 5-7 psi higher so the alarm goes off when something is wrong. Although sometimes the alarm went off completely with no change in PSI or temperature. Can this be so wrong? Or wrong attitude. I recommend TPMS for people with RVs/trailers or even vehicles. I would recommend spending a little more and getting a better quality TPMS.