A personal force field generated by the Holtzman Effect that forms the primary defence against physical attack throughout the Imperium. The shield permits slow-moving objects to pass through while deflecting fast-moving projectiles, making projectile weapons and explosives largely obsolete and returning personal combat to the use of blades. The deadly interaction between a shield and a lasgun beam, which produces a nuclear-level explosion, further restricted ranged weapons. On Arrakis, shields were rarely used because their vibrations drove sandworms into a killing frenzy.