Wikipedia
Strafbattalion is the generic term for penal units created from prisoners during the Second World War in all branches of the Wehrmacht. Soldiers and civilian criminals sentenced to these units were generally poorly armed and required to undertake dangerous high-casualty missions. Strafbattalion were operated and administered by the Feldgendarmerie, the German military police.
By 1943, the course of World War II had turned against Nazi Germany. Due to military losses and the need to maintain discipline by example, the German High Command ordered that further punishment units should be formed from the thousands of Wehrmacht military prisoners held in its military prison. These Strafbattalion, which were under the control of the Feldgendarmerie, were then used to conduct dangerous operations (sometimes akin to suicide missions) for the Heer such as clearing minefields, assaulting difficult objectives and defending positions against overwhelming attacking forces. They were also made to do manual hard labor in front-line locations, building and repairing military infrastructure and defenses.
Prisoners that survived their missions would be deemed 'fit to fight' and returned to the field with the 'rights' of a combat soldier. Although Strafbattalion were mainly used on the Eastern Front, some were sent to the Ardennes on the Western Front during the last major German offensive in December 1944.