This external battery power bank has a lot of power for its "credit card" thin size.  It's true 3500 mAh capacity gives your devices that emergency charge they need while you're on the go.  No more getting stuck away from the house and your battery dies.  Just plug into your portable power bank, which is compact enough to fit in your wallet or bag/purse, and you are back in touch.  This is a high quality power bank that is true to capacity.  You will not be disappointed.  Best choice for emergency uses, to get 50-60% more charge when battery is too low.