The Synergy-class runabout was a redesign of the Styx-class runabout. Synergy utilized "confluent" resources, including tetryon-bichronium plasma flow in its warp drive components, for transitioning into a quantum energy state, making the craft slipstream-capable without QSD, giving it 100% self-sustaining energy efficiency. Incorporating an interphase cloaking device enabled it to "phase" through nonporous matter, bestowing extra, unparalleled tactical advantages. Due to its specialized nature and modifications, Starfleet assigned the experimental prototype, UFS Synergy (introduced in 2378), to its own class, which the UFS Arcadia carried, geared for multi-purpose missions involving up to 20 personnel. These vessels normally carried a crew of 2-4 personnel. (Star Trek: Arcadia)