In SHU, prisoners are generally allowed out of their cells for only one hour a day; they are kept in solitary confinement. They receive their meals through ports, also known as "chuck holes," in the doors of their cells. When Supermax inmates are allowed to exercise, this may take place in a small, enclosed area where the prisoner will exercise alone.
Prisoners are under constant surveillance, light on 24 hours a day ,usually with closed-circuit television cameras. Cell doors are usually opaque, while the cells may be windowless. Conditions are spartan, with poured concrete or metal furniture common. Often cell walls, and sometimes plumbing, are soundproofed to prevent communication between the inmates.