This class of vessel was usually piloted by two Hunters, an Alpha-Hirogen and a Beta-Hirogen. The vessels were equipped with monotanium armor plating, and had dicyclic warp signatures. They were described as having "massive weapons", which had a weapons range of at least 50,000 kilometers. Among their tactical abilities was that of being able to disable other vessels with a type of sub-neucleonic beam, as well as a type of stun beam.
Inside the vessel was a large room which included the control stations as well as walls of trophies and bladed weapons. Also included in this area was technology for producing relics of their prey, including a harness-like construction to hang their prey on while preparing an osteotomy, and large transparent cylinders with fluid in which an enzyme could break down tissue from several species at once. (VOY: "Hunters", "Prey")
The USS Voyager first encountered a Hirogen warship in mid-2374, when they accessed the Hirogen communications network to receive the full message from Starfleet Command. Tuvok and Seven of Nine were hunted down and held as prisoners aboard this ship until Idrin told his Beta-Hirogen to kill their prey. (VOY: "Hunters")
In Star Trek Online, these vessels are identified as "Hunter Escorts".