Just the regular Power Banks that are used to recharge cellphones. They are normally recharged by a micro USB inlet, and offer one or several USB-A outputs.
Just paste this your favorite online store:
and you should get several results.
Double check the specs before buying.
- The outputs should be rated at a minimum of
2A (that's the maximum amount of current that will flow out from it)
- The capacity should be
10000 mAh or bigger (that the amount of charge that can be kept in the powerbank, bigger capacities will give you more autonomy.
An observation about power banks: They are not designed to power a system like chordata. We are using it as a hack, to avoid making users buy a dedicated battery, that will be more expensive, and not reusable. A power bank allows you to get a movable power source for your Chordata, while you can also use it on your daily activities.
I'm saying this because there's always a chance that a particular power bank won't work. It's a matter of trying them, they won't ruin your equipment. I started this thread to get some feedback from other users.