The prison held close to fifty inmates in a single chamber, with no access points save for a single small tunnel, the "chute", sealed by a force field. The chute lead to an airlock on the exterior, where ships docked periodically to deposit food and new prisoners. The fact that the prison was in space was largely unknown to the inmates, most of whom believed that the prison was three hundred meters underground.
Life in the prison was savage. Inmates lived in squalor, and were fitted with a synaptic stimulator called a clamp which induced them to kill each other by inducing edgyness and jumpyness, leading to people becoming aggressive and turning crazy.
In 2373, USS Voyager senior officers Lieutenant Tom Paris and Ensign Harry Kim were sent to this facility after being falsely convicted of a bombing on Akritiri. They were eventually rescued by a team from Voyager, led by Captain Kathryn Janeway and Lieutenant Tuvok. (VOY: "The Chute")