Inmates in American prisons have come a long way from the days of making license plates. Nowadays, prisoners are helping build missiles and other sophisticated weapons, and providing dirt-cheap labor in the process.

While earning as little as 23 cents an hour—and no more than $1.15—inmates assemble electronic components for the Patriot missile, which has been used by the U.S. military and sold to allies like Israel Egypt , Kuwait and Taiwan . The use of prisoners employed by Unicor , a government-owned corporation formerly known as the Federal Prison Industries, saves the makers of the Patriot, Raytheon and Lockheed Martin, a lot of money on labor costs.

Unicor inmates also have contributed work to the building of the McDonnell Douglas/Boeing F-15 fighter, the General Dynamics/Lockheed Martin F-16, Bell/Textron’s Cobra helicopter and BAE Systems’ Bradley Fighting Vehicle.

Prisoners used to make helmets for the military, until 44,000 of them had to be recalled for shoddy quality.

Although Unicor is pitched as a job training program for prisoners, it has some observers worried. William Hartung, author of Prophets of War: Lockheed Martin and the Making of the Military-Industrial Complex , told Justin Rohrlich of Minyanville, “It’s really on the cutting-edge of questionable practices. The fact that it does an end-run around organized labor is a problem. There’s no greater restriction on a worker’s rights than being stuck in prison.”

-Noel Brinkerhoff