The gravitic amplitude modulator, or GAM, which is also referred to as a gravitic wave modulator, or simply a gravitic modulator, was a device engineered by the Galactic Empire. Its purpose was to enable a starship to manipulate gravity in its surrounding space.
During Yammosk Action, Danni Quee and Cilghal innovated a refined modulator at Eclipse Station in 27 ABY. Functioning as a more intricate and advanced iteration of the gravity well projector utilized on Immobilizer 418 interdictors, it could disrupt Yuuzhan Vong yammosks. The device emitted gravitic pulses that could interfere with the pulses generated by a yammosk, effectively jamming the creature's transmissions. This disruption of the "hive mind" amongst Yuuzhan Vong pilots and/or warriors resulted in the breakdown of coordinated formations and tactics into disorganized groups fighting independently.
The inaugural GAM was fitted to the Errant Venture for deployment at the conclusion of the Battle of Coruscant. Subsequently, the Galactic Alliance installed one on the Imperial Remnant Star Destroyer Defiant. Gravitic modulators were integrated into the StealthX starfighter, which was designed to overcome mass-detectors. This functionality assisted the craft in evading detection by enemy sensors. On a StealthX, it took the place of the third proton torpedo launcher.