Very finely made hinged handcuffs. They possess all the features of "standard" cuffs: a push-pin double lock, swing-through pawl, and solid hinge. The key is a small tube with a small flat area at the base. When the key is inserted, the flat area lines up with a matching flat area in the keyhole. The double lock can be engaged with the key by turning in the opposite direction to unlocking as well as with the push-pin.