DS9 activates its graviton emitters
Cheating alien with handheld Graviton emitter
A graviton emitter was a device capable of producing and directing an energy form with gravitational properties.
In 2369, the crew of the USS Enterprise used their graviton emitters to to neutralize tetryon emissions being transmitted through a spatial rupture from a tertiary subspace manifold. Although a group of aliens on the other side of the rupture were temporarily successful in counteracting the pulses, Commander La Forge managed to program the emitters for a full-spectrum pulse compression, and was able to close the rupture. (TNG: "Schisms")
In 2373, the crew of the USS Defiant utilized a phase-conjugate graviton emitter in their tractor beam when retrieving a crashed Jem'Hadar fighter from Torga IV. (DS9: "The Ship")
Later that year, the crew of Deep Space 9 utilized the station's graviton emitters to fire a phase-conjugate graviton beam at the Bajoran Wormhole in an attempt to seal the wormhole and prevent a Dominion invasion of the Alpha Quadrant. The beam was meant to collapse the wormhole's spatial matrix and close it forever, but due to sabotage to the emitters by a Changeling disguised as Julian Bashir, the beam had the exact opposite effect, making the matrix even more stable. (DS9: "In Purgatory's Shadow", "By Inferno's Light")
The same year, Arissa, a visitor to Deep Space Nine, pointed out to Quark that an individual on the upper level of his bar was utilizing a small graviton emitter hidden in his ring to manipulate Quark's dabo table, helping an associate to cheat at the game. (DS9: "A Simple Investigation")