The S4 Sentry, identified as Sentry Skimmer when targeted, is a Core Dynamics remote-control Skimmer commonly used for security operations at Settlements and Surface Ports, though they can also sometimes be found protecting remote cargo dumps. Sentries will either patrol their assigned area or else remain buried beneath the surface until a possible intruder approaches. S4s are quite fragile, and are thus highly reliant on their small size and ability to rapidly maneuver and reposition to avoid incoming fire.
Core Dynamics S4 'sentry' skimmer – this is the most widely used skimmer in the vast semi-automated security and protection industry throughout the galaxy, and a mainstay product for Core Dynamics. Comes as standard with a belly-mounted standard recoil-ready small weapon mount, which will take both kinetic and thermal weapons. Designed with an automated alert system so a single pilot can operate multiple drones.
— Newsletter #94
The vast majority of S4 Sentry Skimmers are armed with a light Multi-cannon, though some models at higher-security installations may be armed with pulse or burst lasers instead. Laser-armed S4s are often also fitted with a shield generator, enhancing their otherwise limited durability.