A modern version of the Hiatt Darby Antique Handcuffs made by Hiatt for centuries. These are made from a "pot" metal which is weaker than the steel used in days past. The keys are made of the same metal alloy and are known to strip if not handled carefully.
These are comfortable single position handcuffs. The locking mechanism is based on a spring backed bolt which is externally threaded. The key is threaded on the inside and is screwed on to the bolt until it retracts.