Nike SB is a product series, while AJ is an independent trademark of Nike. The two are not the same concept.

The SB series is actually Nike's skateboard series and is not an independent trademark. It actually means that these clothes and shoes are designed for skateboarding and nothing more.

And aj is the personal brand created by Nike for Jordan. Although craftsmanship, technology and Nike are completely common, this represents Nike's high-end series and is also Jordan's honor to have an independent brand. This has nothing to do with product functions, because aj also has products in baseball, rugby, etc.