Okay so here is another product review, there are several different brands of this thing, mine is called a power dome it is a combination device for vehicles, it jump starts a car, has an air compressor, light, DC and AC converter, and a usb port ( for some reason).
Well it works great as an air compressor, and I have seen it jump start a car once, it really does have to have a good charge to jump off a car with it. the light is fine beyond one of the leds already burning out.
the ac converter is what I bought it for the most, I got it for a camping trip where I wanted to have as many amenities as possible since I was working near by at the renn fair and camping out where the rennies sleep. The ac converter is easily over strained, by my laptop. It also hates the cold, which I was using it in November, and it was quite cold, both actions made it have a really loud constant beep sound. from other reviews of this device I have seen it happen with them so I know it is not just mine.
I have not used the DC power supply at all I haven't had a need to power car devices away from my car.
I got this on amazon going for cheaper, 79.99 plus shipping made it come in at just 100 dollars, but they are sold at walmart and all other. it really does look like a rugged device, it just needs a bit more kick to power a laptop, but the battery just left in my car to pump up my tires when needed lasts for a decent while.
I think it is a must have for in the car, just to pump up a tire and jump yourself off rather than looking for a good person to help.