Well, imtu (as an example) it's the Nishemii class Far-Trader. A now largely infamous and out of production design which once backed the dream of a safe regular interface line between non-Imperial and Imperial worlds along the border in the Marches.
Long story short, the line failed, several examples fell into the wrong hands, and it's now mostly used by pirates and not in favour for legitimate use due to the design faults that saw it so easily hijacked, and the fact that so many other Captains will tend to scream "CORSAIR!" every time you show up.