The Gordon 9mm Submachinegun (Sterling SMG) it is chambered for 9x19mm, has a 30 round magazine capacity, can use FMJ, Dum-Dum, incendiary, and cyanide-tipped ammunition. H.A.R.M.'s henchmen also use it frequently in the later levels.
A popular submachinegun due to its reliability and stylish design. While holding it by the side-mounted magazine is not recommended, most agent do.
Unlike the Walther MPL, the Sterling SMG cannot mount a sound suppressor. For some reason, the ingame version has a large cross-shaped muzzle flash, despite the barrel having no visible flash suppressor.