All kinds. Almost all of 'em. A Duty technician is the best in the whole Zone, got that? I can upgrade your machine gun like no one else. I can make you bulletproof like no one else. Point is, I know my stuff. - Thunderov
He was Duty's technician during the events of Clear Sky. Unlike most people in The Zone, Gromov is a rather silent person. Gromov can upgrade a wide variety of weapons including NATO class weaponry and the only one who can upgrade the RP-74 machine gun. However, Gromov does have some limitations with armors except the Exoskeleton, he cannot install the final Psy protection upgrade in the anomaly protection tree on Tier 3 armors. He also gives a job to get some plans for upgrading the RP-74. Gromov is one of the few technicians who can upgrade the Exoskeleton.