I have something similar that I bought about a year ago. Actually, I bought two of them. One to keep in my motorcycle and one to keep in my travel bag. I bought them primarily to use as portable power packs for my phone and iPad. I travel frequently for work and it comes in handy for charging them when you experience flight delays, etc. Not sure the power stats, but I've had absolutely no issues with mine, ever. It's amazing how long the charge on them lasts, but I can't even tell you because they literally lasts for months. I paid about $100 for each of them.
The power button is on the side, and when you press it once, it lights up the blue LEDs that tell you the percentage of available power reserve; 4 lights=100%, 3 lights=75%, etc. On the end, from left to right; the outlet for the 12vdc jumper cables, an LED flashlight (press the power button twice to turn on/off), the USB port for plugging in your phone/tablet to charge, and then the outlet for recharging the power pack. This power pack weighs about 30% more than my iPhone, so it's super convenient and easy to travel.
I never thought it was going to be too necessary to use as a jump pack, but worth the cost for recharging devices. But if you've ever spent a lot of times riding street motorcycles, you'll eventually have battery issues... or ride with someone who will. Like I said earlier, I bought one to keep in my bike, mainly to keep my phone charged while laying in the saddlebag. The jumpers are small enough, so I threw those in there too. While I was in Sturgis, I ran into about four guys who were broke down with a dead battery. I remembered I had the jumpers, so I offered to help, but I wasn't sure how well this would REALLY work. All four times, people laughed when they saw what I had. Right up until their bike started. And even more surprising, all four bikes started on ONE charge, and it still has 75% power left, after laying in the saddlebag since the first week of August! I'm sold on these little things and the technology built into these.
A buddy of mine showed me his, and that's where I discovered these. He lives up in Edmonton, Alberta and starts snowmobiles and his truck all the time with his. But I'll admit... if I'd never seen it used and worked myself, I'd swear it was impossible. Love these little gadgets.