We've all broken down on the side of the road at least once, I'm sure. I learned the hard way to always keep some emergency items on hand. I always have at least one bottle of each type of fluid, tire plugs, fix-a-flat, cleaners, road flares, jumper cables, a flashlight, and my personal favorite, the jump box.
I love having the jump box. If I'm stranded somewhere, and nobody can jump me, I can just hook it up, and start the car that way. It's super convenient. It's this exact one here.
While it's not super heavy-duty, it gets the job done, and it was bought for me, so I can't complain there. Like I said, I love this thing.