My SBS TTCB100002UF powerbank, which charges with 10 W of input power, has two USB ports rated at different outputs: 2.1 A and 1.0 A for output.
The 1.0 A-labelled port also delivered 2 A, just like the 2.1 A port. It could have probably delivered 3 A too, but I have no device that charges 5 V at 3 A.
Now, what is the possible difference between these ports? Is it about priority on simultaneous usage?