The Imperial Customs Frigate was manufactured by Rendili StarDrive, the builders of the larger Light corvette also used by the Customs Office. Though it was slower, smaller, and less durable than the Light Corvette or the Guardian-class light cruiser from Sienar Fleet Systems, it required a smaller crew, and its six heavy laser cannons had significantly greater firepower at short range.
Like other vessels used by Imperial Customs, it was able to do battle with most smugglers' light freighters, the forces of small-time pirates, or even Rebel starfighters. Of course, it was completely outclassed by capital ships, which generally required the intervention of the Imperial Navy.
Sometimes during Roark Garnet's captaincy, the Dorion Discus freighter caught the attention of the Customs Frigate Assessor. The Discus disobeyed the shut down order and tried to escape. After a warning shot, the frigate began to shoot at the freighter, but it entered hyperspace.
While primarily used by the Empire, the Customs Frigate was also sold to local governments for their own small navies, and at least one vessel, Battle of Yavin, was captured and used by the New Republic. It was also coveted by pirates, who captured the vessel or bought illegal copies of the design built in criminal shipyards. One such pirate vessel was the Counter-Puncher, commanded by Tor Skylow and crewed by Imperial deserters.
The Counter-Puncher was a modified Customs Frigate.
The stats of the Imperial Customs Frigate first appeared in the Star Wars: The Roleplaying Game. Later these stats were given to the Guardian-class light cruiser and the frigate got new ones.