There are more than 3,500 inmates doing time in Pelican Bay. Of these, 1,500 of the worst in California live in the security housing unit (SHU), a residence reserved for prison gang members and others who have proven themselves violent and dangerous. SHU inmates stay locked in their "houses" 22 1/2 hours a day, allowed out one at a time to shower and take solitary exercise in a cement yard no bigger than a handball court. There is more to Pelican Bay than the SHU, however; there is a conventional level IV (very maximum security) prison that operates at 190 percent of capacity and a Level I facility called "the ranch," which houses low-risk inmates who work in the prison and the community. The SHU and its regimen has given Pelican Bay its reputation as a tough prison. Taking up half the sprawling prison facility, the SHU is surrounded by 50,000 volts of electrical fence, watched over by three gun towers that are staffed around the clock. Inmates live in windowless cells, fronted with perforated steel instead of conventional jailhouse doors, so as to minimize the throwing of spears and other weapons. Approximately half the inmates are double celled; the other half live alone. The SHU has been the target of an inmate lawsuit known as Madrid v. Gomez. In this case the judge found deficiencies in three areas: use of force, mental health care, and physical health care. Efforts to improve the prison's performance in these areas are described.