Hiatt adjustable Darby handcuffs

 Here is a very good condition adjustable Darby handcuff from Hiatt. This is the 115 model with one original key. The keys for adjustable Darby handcuffs from Hiatt are often marked with an "A". 

These sold for £34 or $45.07 with 5 bids

Above, close up detail of the hinge and makers mark stamp.