ARC casters were essentially revamped E-11 blaster rifles, modified to emit potent electrical surges. These surges possessed the capability to neutralize electronic devices and inflict lethal internal damage to living organisms by essentially boiling them. These weapons saw action with units such as Phase Zero Dark Troopers, Phase II Dark Troopers, and the Emperor's Royal Guard, all of whom served under the banner of the Imperial Army. Furthermore, X1, a practitioner of the Dark Side Adept, also made use of this weapon throughout his endeavors.
The weapon was equipped with a charging mechanism that enabled the user to build up a powerful electrical discharge directed at the intended target; when fully charged, this discharge could spread to as many as four additional targets. This class of weapon bore similarities to the plasma disruptors that were initially issued as personal sidearms to clone pilots who were dismounted. When employed, the electrical burst from the weapon could inflict substantial damage to the circuits and internal systems of opposing droid units. The designation of these weapons stemmed from their capacity to "arc" or jump from one target to another.