very high quality model of the mobile turret from the game Portal by Valve.
The Aperture Science Sentry Gun has a single red eye, sleek appearance and predominately white color scheme common to most Aperture Science technology. Sentry Guns have only been seen in the Aperture Science Enrichment Center acting as guards in Test Chambers and maintenance areas.
Sentry Guns often speak in a child-like, artificial voice similar to GLaDOS and toilets within Aperture Laboratories. They have a strangely polite demeanor, which is in direct contrast with their deadly behavior. They will even forgive Chell for knocking them over. In one scene in Portal 2, a Sentry Gun stuck inside the Aperture Science Pipe Network attempts to get Chell and Wheatley's attention. At Wheatley's encouragement, Chell ignores it, but the Sentry Gun politely says 'thanks anyway.'
The Sentry Guns are armed with dual machine guns, targeted with a visible laser beam. These weapons are normally hidden inside the body, during 'sleep mode.' When the Sentry Gun is alerted, they will deploy, and fire at any visible target (usually Test Subjects or intruders in the labs). When no target is in range, the Sentry will scan back and forth across the area, and return to sleep mode after several seconds if no further target is found. Shells for the guns are simply dumped into the hollow body; this allows for an almost unlimited supply of ammunition.