Cloaking device
Cloaking devices are devices that allow the user to, by stealth means, evade or ambush enemies. They come in at least three variations. Some cloaking devices are mere sensor shrouds preventing the user from being detected electronically, while more sophisticated cloaking methods render the user invisible to the eye as well. Of the latter type, some allow the person cloaking to "see out" while earlier, simpler models blind the user as well, meaning that they need to de-cloak to adjust course or take sensor readings.
History
While both the Terran Confederation and the Kilrathi strove to develop feasible cloaking technology early in the war, it was the Kilrathi who were able to first develop a usable device which they deployed in their Skipper missiles. This early version was a blind cloak which required the missile to de-cloak at regular intervals to maintain a target lock, and hence their being nicknamed "Skippers" by Confederation pilots. They proved to be an effective tool in the Kilrathi arsenal and saw use right to the end of the war. New versions of the Skipper missile were developed and tested for the delivery of biological weapons in the Locanda System mere months before the end of the war.
Further development was needed to make the system viable for fighters, and the earliest report of a sensor shroud style cloak was reported by pilots of TCS Tiger's Claw in 2654. Only a few years later, the Kilrathi had developed a full optical cloak usable on a fighter, and a handful of Strakha (the Kilrathi word for stealth ship) fighters destroyed the Tiger's Claw. The Kilrathi stealth program was set back ten years, though, when Kilrathi Prince Thrakhath destroyed the shipyards at Gorah Khar to prevent the stealth technology from falling enemy hands during that system's rebellion from the Empire. With the shipyards and stealth labs relocated, the fighters were redeveloped and by 2668 the Strakha fighters held the Confederation at a disadvantage.
The Confederation's own stealth technology didn't mature until near the end of the Terran-Kilrathi War when the technology was introduced in the Excalibur fighter, which allowed a fighter wing from TCS Victory to deliver a fatal blow to the Kilrathi home world itself, forcing the surrender of the Kilrathi Empire and ending the war. It didn't take long for the technology to be developed for use on the Arrow Eclipse, and Lance fighters. By the beginning of the Nephilim War, cloaking devices were standard on all new Confederation designs, though Nephilim technology rendered the devices useless.
Alternate History (The Real World)
Cloaking devices first appeared in a Wing Commander game in Wing Commander II: Vengeance of the Kilrathi, and the devices continued to be used in subsequent games with the devices being usable by players in Wing Commander Armada. The animated TV series Wing Commander Academy, the Wing Commander movie, its novelization and accompanying handbook helped to fill out some of the history of the device's use. Wing Commander Prophecy removed the cloaking device from the game for game-play considerations requiring the removal of some early missions from the game that were to explain their ineffectiveness. Cloaking devices made a return though in 2007's Wing Commander Arena.