Supermax is short for super-maximum security

Supermax is short for super-maximum security. Supermax prisons are places intended to house violent prisoners or prisoners who might threaten the safety of the guards or other prisoners. Some prisons that are not intended as supermax prisons have control units in which circumstances are similar. The concept is that solitary confinement and sensory deprivation will bring about behavior changes (What is a Supermax prison). Twenty years ago, supermax prisons were rare in America. Today more than two-thirds of states have some sort of supermax facility (Mears). Long-term solitary detention, in which a prisoner is cut off from almost all human communication and interaction for an extended period of time, is a practice that is almost exclusive to the United States. While many contest the benefits of solitary confinement, others contend that it is needed for some high-profile and dangerous criminals (Trent).
Supermax prisoners are housed in small cells for approximately 23 hours out of every day (What is a Supermax prison). They have almost no contact with other people. There are no group activities, no work, no educational chances, no eating together, no sports, no getting together with other people for religious services, and no attempts at rehabilitation. They are not given contact visits. Prisoners are kept behind a plexi-glass window. Phone calls and visitation freedoms are severely limited. Books and magazines may be denied and pens controlled under certain circumstances. TV and radios may be forbidden or, if allowed, are controlled by guards and not prisoners (Mears).
Prisoners have very little or no personal privacy at all. Guards watch the inmates’ actions by way of video cameras. Communication between prisoners and the control booth officers is mostly done by way of speakers and microphones. An officer at a control center may be able to monitor cells and corridors and control all doors by electronic means. Characteristically, the cells have no windows. Lights are restricted by guards who may leave them on night and day. For exercise, there is typically only a room with high concrete walls and a chin-up bar. Showers may be restricted to three per week for not more than ten minutes (What is a Supermax prison).
Some sources propose the main rationale is to protect other inmates and staff. How this protection takes place is unclear. The rotten apple theory suggests that removing the most violent inmates helps stop other inmates from committing assaults and infractions. An alternative argument is that supermax prisons incapacitate the worst inmates, preventing them from injuring others. According to this viewpoint, there is no rotten apple effect per se. Rather, any overall decrease in prison violence results totally from incapacitating the most violent and serious offenders.