TKS Type-E Patrol Handcuffs
While pretty typical, at least outwardly - they do have a few neat fetures. They are made of Aluminum making them rather lightweight. They use a non-standard key making them somewhat more secure. Finally, in order to double lock them, it is necessary to pull out the swivel a bit (B) and then push a pin (A). In order to unlock the double-lock, it is necessary to PULL the chain out of the lock case (B) before turning the key. The idea being that it is difficult to both pull the chain and turn the key while wearing them. Another security bonus.
It should be noted that these cuffs are nearly identical to Latrobe LTH Handcuffs.