WW2 'Come Along' or 'Nippers' Prisoner Restraints.
These 'Come Alongs or 'Nippers' are WW2 made wrist restraints.
They would be wrapped around the captured persons wrist and the toggles would be twisted around and the three knots would dig in to the wrist, making the captured person easy to control, hence the name 'Come Alongs'.
Having tested this theory I can concur that they are very very effective.
These Come Along restraints were picked up at a French Brocante (Antique Fair) and we were told they were used by the French Resistance.
A very nice piece of WW2 improvised history.