I have used my fair share of power banks and car jump starters and this one I am solely reviewing for a jump starter since I have not personally used it for anything else yet.I bought this for my wife to keep in her car and took back my ugly, bulky jump starter. Her car has trouble starting in the cold weather sometimes, along with her co workers not closing a door all the way and needing a jump with cables. That's where this guy shines! She already had to jump 2 cars and it was easy enough for her to use as well as showering her co workers how easy it is. I ended up sending her the link to this so she could buy one for her and her husband.My first test with this was to see if it can start my car solely off it's power. I disconnected the terminals on my battery and hooked this guy up, waited a second and turned it over. Started like it was still connected to the battery.Time will tell how long it will last but so far it has already paid for itself and made my wife look like a hero!