Bags with external plugs are wired internally and allow to connect a power bank (not just that of Piquadro) so you can access from the outside to charge a device or the same power bank.
You can use the micro USB and USB ports on the exterior of your Piquadro product as if they were the micro USB and USB ports of your Piquadro battery pack (or your generic power bank).
To recharge the Piquadro battery pack (or your generic power bank) using the expansion plate, connect the micro USB cable placed inside your Piquadro product to the micro USB port of your Piquadro battery pack (or your generic power bank).
To recharge your device using the expansion plate:
•Connect the USB cable inside your Piquadro product to the generic power bank USB port or to the USB port marked with the thunderbolt symbol of your Piquadro battery pack
•If your generic power bank does not have a USB port, you can buy an adapter separately (USB female + MICRO USB female) so you can connect the cable with micro USB output of your generic power bank to the cable with USB output inside your Piquadro product. In this way you can recharge your device using the expansion plate outside the product.