Froggatt Darby Handcuffs

Here is a very nice set of Darby handcuffs from Froggatt. These sold for $79 with one bid. It may have been had a Buy It Now option because I didn't see it, and it would have certainly sold for more if it was a straight auction. Sometimes you find an item that's not only rare but also priced way below market trends, like the near mint Bean Cobb leg irons I got for $30 back in November. 

Below, detail of the Froggatt makers mark stamp and the hinge. 

Above, note how the key doesn't have a shoulder to bear upon the keyway; this key would have to be pulled up to compress the spring. This is likely a replacement key, but perhaps not, as the top portion looks appropriate for this design.