These weapons, the machine guns, along with its antenna are normally hidden inside the body, during the Turret's 'sleep mode'. Upon seeing that there are no more targets, the Sentry Turret will return to sleep mode after three seconds. When no targets are in visual range, the Sentry will scan the area in a sweeping motion with its laser targeting beam. They will begin to fire at any visible targets (usually Test Subjects or intruders). Upon visual acquisition of the target, the Sentry Turret will come to full alert, and the machine guns will emerge. The Sentry Turrets are armed with two dual machine guns, which can only be armed once a target comes within visual sight.It can later be seen and picked up in the incinerator room. At Wheatley's encouragement, Chell ignores it, but the Sentry Turret politely says 'thanks anyway' with a hint of shattered hopes. In one scene in Portal 2, an Oracle Turret is seen stuck inside the Aperture Science Pipe Network, who attempts to get Chell and Wheatley's attention. They will even forgive Chell for knocking them over, suggesting they do not want to kill Chell. They have a strangely polite demeanor, which is in direct contrast with their deadly behavior. Sentry Turrets often speak in a sweet child-like, artificial voice similar to GLaDOS and a lavatory bowl within the Enrichment Center.Sentry Turrets are commonly seen serving as (rather ineffective) guards in the maintenance areas of the Enrichment Center, and during testing as an obstacle to the Test Subject. The Aperture Sentry Turret has a single red eye, sleek appearance, and predominately white color scheme common to most Aperture Science technology.In Portal 2, however, Turrets will only follow the player behind glass. In Portal, Turrets will shoot the glass when the player is on the other side. Additionally, the Discouragement Beams or Emancipation Grills can be used to completely destroy them. This can be done by picking them up and dropping them, or using any object to tip them over. The most common method is knocking them over, causing them to flail and fire wildly before deactivating. Turrets can be avoided, disabled or destroyed in a number of ways. If the latter occurs, Turrets will briefly search for the test subject (as indicated by the movement of the targeting laser), after which they will revert to a standby state. They will continue to fire until the target is dead or moves out of sight. Moving into their angle of sight however, will cause Turrets to deploy their guns shortly after greeting Chell or Atlas or P-body before opening fire. When test subjects are out of sight from the Turret's presence, they will maintain a standby state and will remain motionless with their guns retracted.

Almost all of the space within the Turret is devoted to storing the ridiculously stacked ammo, explaining the nearly infinite supply of ammo when firing. The central part of the chassis holds their red eye, which emits a targeting laser. They are seen as incapable of independent movement, but can open each side of their chassis (their 'arms') horizontally in order to reveal two gatling guns. Sentry Turrets are tripod robots that appear in every game in the Portal series.

Portal turret in real life size