It operates with a rechargeable battery. So, at first, you charge it and everything is fine. Most of the time, it stays in the trunk unless you have a car that happens to break down constantly. So, it remains uncharged and the batteries go bad even though they are rechargeable. I randomly took it out to see if it works and it didn't work, and I haven't used it since the first charge. To be fair, it only does its job if you have in mind to constantly charge it. My low rating is because it makes it inconvenient, and there is no chance, not even one in a million, that I would put it inside during the day to charge. We buy items to make our lives easier, not harder.