The Deathwatch Graviton Cannon is a modification made by the Deathwatch Techmarines of Watch Fortress Erioch in the Jericho Reach of the more common Space Marine Grav-Gun. The Deathwatch Graviton Cannon possesses a higher graviton output and has proven decidedly more deadly when unleashed on the Deathwatch's foes.
Where the common Grav-gun has but one setting that affects the gravity in a sizeable area, the Deathwatch version can also focus its energies into a continuous tight beam of incredibly dense gravity waves.
- Deathwatch: Rites of Battle (RPG), pp. 137-138