In English ‘ringkragen’ means ‘ring collar’ and was originally a part of a military armoured suit that protected the throat. Over time, it became a symbol of status within an organization, i.e. a standard (flag) bearer or, in this case, a sign of police authority.

The duty gorget and readily identifiable badge of office of the World War II German Feldgendarmerie (military policeman) was only worn while on duty. It was known as "Kettenhunde", which translates to ‘chain dogs’. These officers were hated, feared and loathed by his own countrymen.

snip

The Feldgendarmerie was reformed in 1939 when the German Army mobilized for war. The tasks the Feldgendarmerie were called upon to perform were much the same as military police do in any army: control of traffic to and from the front line, maintenance of order and discipline, rounding up stragglers, arresting deserters and looters, interrogation of suspects, anti-partisan patrols, escorts for prisoners, manning checkpoints and checking IDs and travel passes as well as general policing duties.

Although they did carry out some traffic control duties, these were the real "head hunters." In the closing stages of the war they were tasked with rounding up stragglers and any man, or boy, fit enough to hold a rifle or a Panzerfaust. They packed these unfortunates off to the front line to try and stem the unstoppable Russian advance. Their power was absolute and any man suspected of being a deserter could be summarily executed by shooting or hanging. A common scene in the crumbling Third Reich was that of a soldier hanging from a convenient lamp post with a sign around his neck proclaiming his desertion and disloyalty to Reich and Fuhrer. Authorized to settle any dispute at the point of a gun they often did. They held the power of life and death and used it as they saw fit.