A crystal gravfield trap (CGT) represented a costly type of sensor that utilized a manufactured crystal matrix for the purpose of identifying and sensing variations within the immediate gravity field. The better crystal gravfield traps were capable of identifying and sensing variations across a distance of hundreds of thousands of kilometers surrounding the unit. These traps could be rendered ineffective by the presence of significant mass, meaning they were unable to detect a ship situated on the opposite side of a planet due to the planet's mass.
CGTs stood out as the sole sensor capable of reliably detecting a ship employing an active cloaking device. Bartokk assassins, in the employ of Groodo the Hutt, possessed a CGT sensor, enabling them to detect the cloaked Sith Infiltrator piloted by Darth Maul.
When Grand Admiral Thrawn initiated a blockade of Coruscant using a number of cloaked asteroids, their location became a matter of utmost urgency. As the New Republic lacked access to any CGTs, they found it necessary to attempt the steal of one from the Imperial installation located at Bilbringi. General Garm Bel Iblis of the New Republic previously had one before the Battle of Svivren, but it was subsequently lost.
The LightStealth-18 Reconnaissance Ship, which was used by the New Republic during the Yuuzhan Vong War, was equipped with such devices as a component of its sensor suite.
The Imperial Remnant utilized Imperial Patrol Frigates equipped with crystal gravfield traps, using them as long-range deep-space probe vessels.