During the War Edit
The Ministry Mare of the Ministry of Awesome, Rainbow Dash, disliked the very durable, yet bulky design of the PipBucks made by Stable-Tec. But since giving away the benefits such a device granted both in battle and everyday management was out of the question, the Stable-Tec developed a custom edition of the PipBuck, matching the needs of the Ministry Mare, the PegasusBuck. To keep the original possessor's body aerodynamic the device was planned to be implanted into the right foreleg of the chosen pony. Since this much less bulky version of the PipBuck was created for the Ministry Mare of the Ministry of Awesome, Rainbow Dash, only, it isn't compatible with other ponies' bodies.
After the discovery of the two elements necessary to build a Continuum Reactor, Stable-Tec took the chance of creating an independent energy source, but due to a lack of resources, there was only one ever built. In the final days of the war, when projections made by Stable-Tec predicted a near end of Equestria, a CEO of Stable-Tec, Scootaloo, decided to implement the Continuum Reactor into the PegasusBuck to prevent future ponies from damaging the reactor by trying to remove it from its original place. Several changes had to be made, but due to the very small size of the reactor, the combination was possible, ending up in the device PegasusBuck 20 "Salvation". The nickname comes from the likely possibility of the satisfaction of the post-war ponies' demands for energy by this reactor alone.
Post -War Edit
Unfortunately the complete device was never given to anypony, resulting in it staying sealed away in a storeroom of Stable-Tec for more than two hundred years. The storeroom's mainframe was provided with several protocols which would kick in in case the dead-pony-button would reset is one time per day.
Due to the most certain death of any pony associated with the old government of Equestria, the one-hundred-and-fifty-year-protocol, which was the one active as the sealing was finally breached, made the device accessible for any pegasus happening to walking into the DNA-seal sealed core chamber..
The PegasusBuck 20 "Salvation" features most of the standard spells of a normal PipBuck, with the only difference of it being only compatible with pegasus anatomy.