I received this as a free review sample. It does work as claimed (I tested it on a vehicle and my brother used it to start a number of motorcycles that he was restoring. The subtracted star is because this not only needs a wall wart that uses a barrel connector for charging this battery (included), but does not include a vehicle charger that works from a lighter socket. Seriously, that makes no sense, but I cannot fault the performance of this jump starter aside from that. To be fair the included wall wart is rated at 14V at 1 Amp, but I have a different brand of charger that works as well as this one that uses standard USB for charging. However, this one will actually fully charge up in about three hours, whereas some of the other units that I have tested take 10-18 hours. This one is a little more robust than other chargers that I have used. Many have an operating range in the 32 to 110 degrees F range, whereas this one will work in the -4 to 140 F range. That means that you can safely store it in your vehicle in most hot areas and it will still function in the heat or cold. Note that if you intend to use this to power a phone or tablet that while it will hold 9000mAh of stored power, your effective backup will be around 6300mAh. That is due to losses all polymer lithium batteries - regardless of brand - incur due to heat and transfer and even cable inefficiencies. This is not a problem since all 9000mAh batteries act this way, but I wanted to point it out to set expectations.