This is a device that will charge your USB devices, provide light in an emergency, provide 12 volts for other devices, AND Jump-Start your car in case of a dead battery. It comes complete with battery clamps for starting engine and a USB charging cable, to recharge the unit from auto lighter socket or AC wall wart charger (up to 3 amp charging rate). I would not recommend it be charged directly from your computer USB, I would worry that it may demand more current than your computer is capable of providing and possibly harm your computer.
It comes with a zipper hard-case for storage and a very good instruction manual. The case is just the right size for storing in the back storage of my vehicle, which is where it will be stored. I would recommend that you periodically recharge the unit to keep the internal batteries topped off, ready to use in an emergency. It costs much less than having to call a roadside service to jump-start your vehicle. It gives you a sense of well-being, knowing you will not be stranded on the side of the road.