Prisons have unique security requirements. Weapons can be smuggled into prisons from the outside, or located/fabricated within. Invariably, these are used for illicit purposes. Prison management has expressed the need to screen large numbers of prisoners in short periods of time as they move throughout a prison facility or campus.
According to the U.S. Bureau of Justice Statistics (BJS), there are over 2,000 state & federal prisons in the United States with 1.5M adults incarcerated in U.S. federal and state prisons. Also, prisoners frequently work in factories operated by the Federal Penal Institute, and as of September 30, 2011 there were 14,200 inmates employed in 88 FPI factories.