This is an honest review of this item, which I purchased full price on Amazon.com:
I bought this as an alternative to jumper cables our vehicles emergency kits. As you all know jumper cables require you to have another vehicle, these do not. This comes in very handy when you are alone out somewhere, at night with minimal help around.
From my testing on our 2015 Subaru Forester 2.5i (OLD BATTERY, Replaced now) I was able to jump it 9x without any problems. I then tested its cellphone recharging ability, I was able to charge my iPhone 8 Plus full 5x without any problems.
I was able to recharge the jump pack via usb in about 9hrs, after the first use and recharge I preformed the tests again with pretty much identical results minus one phone charge.
For the price, this is the best bang for your buck jump pack you can buy. Its compact size is also a huge benefit! So if you are in the market for a jump pack, consider this one first!