Yes, all of our products are certified and will have the appropriate markings on the products.
For those power banks with a power button, you must press the power button first to turn on the power bank. There are a few AUKEY power banks that do not have a power button that will begin charging as soon as it is plugged into the device.
Capacity is measured in milliamperes (mAh) on power banks. As a general rule, the more mAh in the power bank, the more times you will be able to charge your device before having to charge the power bank again.