The hyperwave inertial momentum sustainer (HIMS) was a system designed to effectively counteract an interdiction field. A gravitic anomaly sensor in the system provided a ship's hyperdrive the ability to quickly shut off, preventing damage from sudden realspace reversion upon encountering a gravity well. At the same time, the HIMS could produce a static hyperspace "bubble", sustaining the ship's presence in hyperspace while accumulated forward momentum propelled the vehicle along. While the HIMS could only keep a ship in hyperspace briefly, it was sufficient to pass through nearly any interdiction field, with the sole exception being the gargantuan field that Centerpoint Station established, covering the entire Corellian sector. In addition, the HIMS could only be used to prevent a ship from being pulled out of hyperspace; a ship in realspace would still be unable to engage its hyperdrive within an interdiction field.
"HIMS" is sometimes used by fans as a designation for Imperial starships, standing for "His Imperial Majesty's Ship"; however, there is no canonical basis for this.