Almost as thin as a credit card. Yet it contains 1300mA of power , enough for 75% charge of modern day smartphone. This impossibly thin power bank (only 0.22 inch!) rests discretely in your wallet ready in case you need it. Push on the side button's LED to check your Powercard battery level: Green color : Full charge. Blue color : Half charge; Red color: you are at 25% or less.