Allos' species were an advanced humanoid species native to a planet in the Delta Quadrant.
While a still pre-warp civilization, this species operated ships that operated with many advanced technologies, such as tractor beams and particle weapons; likewise, they were capable of traveling between the planets of their system at impulse speeds matching and nearly overtaking the maximum impulse of an Intrepid-class starship.
In addition to these moderately advanced spacecraft, they also maintained a research facility on an M-class moon inwards from their world. As of the 2370s, their resources were nearly gone. They had started research into synthesizing Omega molecules, which they hoped would be their salvation.
However, in 2374 the facility suffered a major disaster, which damaged subspace in an area around the system. Voyager detected the disaster and violated the Prime Directive in order to successfully destroy all molecules, per the Omega Directive. (VOY: "The Omega Directive")