The v- was a unit of energy, used to characterize the amount of deliverable energy in a single tube charge for an artillery weapon. It was based on the energy required to excite a 400 cm by 8.5 cm rod of standard-purity vacierite to the point where a double-packed particle emission of 1024 g2-ions in a coherent beam would be produced. Republic Sienar Systems, the precursor to Sienar Fleet Systems, originally developed the unit. It was later one of many units used by the Imperial Service to rank and categorize artillery pieces.