Penal military unit
A penal military unit, also known as a penal formation, disciplinary unit, or just penal unit (usually named for their formation and size, such as penal battalion for battalions, penal regiment for regiments, penal company for companies, etc.), is a military formation consisting of convicts mobilized for military service. Such formations may consist of military prisoners convicted under military law, civilian prisoners convicted in civilian courts, prisoners of war who have chosen to side with their captors, or a combination of these groups.