Mattatuck Handcuffs

 

Here is a decent pair of Mattatuck Handcuffs. They sold for $179.99 on eBay with one original key.

These are fairly rare, certainly more rare than Towers Double Lock handcuffs, Hiatt Darby handcuffs, or Bean Cobb/Prison handcuffs. They have 3 bent links like Towers, non-swivelling clevises, and use a double pronged key much like the Marlin Daley Handcuff, which also has three bent chain links. Otherwise these are very similar to Towers Double Lock insofar as the shape and design of the shackle and the lock body shape. The clevis attaches to the lock case itself whereas the Towers clevis is integrated into the hinge. 

This design has a lock activating mechanism that works much like the Bean Cobb/Prison/Giant activating buttons. The key in the keyhole could be used to unlock the cuff and then further turned to disable the lock. The cuff could be carried closed and open freely. It was activated not by a button but by pulling the shackle all the way back/open until it clicked, at which point the lock would activate and be ready to lock upon closure. 

The matching leg irons below are currently for sale with the asking price of $165.99 with no key. These leg irons have a strange round barrel key, compared to the double pronged key for the handcuffs above. There may have been different production runs of these models and the lock may have evolved over time. They have a bent link chain like Towers. 

These are very similar to Towers Double Lock Leg Irons. The shackle looks almost identical. The lock case here is very similar as well, but the chain being attached to the lock case seems awkward, particularly on the leg irons.