Deutsche-Polizei High Security Handcuffs

These are hinged handcuffs from the former East German Republic (GDR). This model is the "high" security model in that the bows do NOT swing through. The cuff is made from cast and machined aluminum. The double lock is engagend by turning the key around 120 degrees - 240 to open it, 360 to disengage the double lock (and the key can be removed). If you have the cuff double locked, you can turn the key 240 deg to adjust the fit, but if you turn the key backwards (instead of finishing the 360 deg) it stays double locked. The double lock is basically a SECOND ratchet that moves in line with the first one. These mechanisms are notoriously problematic and fail when enough pressure is applied to the bow (which only makes the lock tighter!)