Maricopa County Jail in Arizona is the 4th largest jail system in the world. In 1993 it exceeded the maximum number of inmates allowed in its facilities. It was estimated that construction of a new facility would cost approximately $70,000,000. Sheriff Arpaio ordered that a Tent Jail be constructed utilizing inmate labor. It consisted of Korean War era tents donated by the United States armed forces, and a 50 ft (15.4 m) observation tower with a vacancy sign mounted on the front. The final cost of the project was approximately $100,000 and it is capable of housing over 2400 Inmates. All inmates housed outside in the open tents (N yard for males and O yard for females) are "volunteers" in the "Working Inmate Program" and must agree to work an assigned job and comply with the Sheriff's grooming standards. Inmates who decline to work or refuse to groom themselves are relocated inside a hardened facility along with the rest of the jail population. All inmates wear pink socks and underwear.