Made by the Belgian armaments company FN-Herstal (and so marked), these cuffs are unique in that their key is actually a magnet. The key is used to pull the latch away from the arm, allowing it to be disengaged. Applying more force to the key pulls it out of the cuff and frees the latch to function normally. In most other respects these are basic swingthrough handcuffs without a double lock. Their shape is the more secure elliptical one favored by French and German cuff manufacturers.