Hi @Geoff56, welcome to our forum!
We do not have our own power banks, but I'm not quite sure that I understand why it won't fit in normal power banks, could you please elaborate a bit?
The USB port on the device is USB Type-C which is the new standard as has been that since around 2-3 years ago, so there should be plenty of power banks that supports this and the other "side" of the cable is a normal USB-A port (same as on a PC/laptop).
I hope that helps!
