I had high hopes for this product especially the reviews. Now I'm wondering how many of these are real estimates. I bought this because one of my car's tires was a little low from a recent cold front. I figured it would be better to have it on hand in situations like this than going to the nearest gas station. The item came quickly and was well packaged. It was very light and seemed well put together. I read the instructions and went to connect it to my car. Everything lit up as it should and I even hooked it up to a tire and the pressure gauge was accurate to within 0.5psi. As soon as I set it to the required pressure and turned it on, it shorted out immediately. I found this strange and my first impulse was to look back at the manual and check the output voltage on my machine. The plug on my car was the right size and I followed the directions to the T so nothing wrong with that. When I looked at the fuse on the device itself, I noticed that it blew right away, which was pretty amazing. But of course that happens every now and then, doesn't it? I was still trying to convince myself that this is within the normal range and that bugs do happen from time to time. So I replaced the fuse with the extra one that came with the kit and tried again. This time I hooked it up to my husband's car, thinking that despite having the correct voltage, my car was surely overpowered as it was the newer of the two. No, the same thing happened. As soon as I turned it on, it immediately turned off again. I have already returned it for a full refund because I followed every letter of the instructions and it died on me twice. I do not recommend this product at all and I strongly recommend everyone to do their research before buying as there was no reason for this device to die so many times and so quickly as if every step was done right. My apologies for occasional glitches, but not for multiple incidents in a row on the same hardware.