These unique Kyoung Chang high security handcuffs are very impressive.  Instead of the single ratchet of normal handcuffs these 701s have no less than three independent ratchets.  Additionally there is a anti shim bar between each of the two outside ratchets and the middle one. 

This makes it virtually impossible to shim the handcuffs and very difficult to pick the lock.  They are also double locking with the slider operated by the pin on the key.  Every collector should have a pair of these excellently designed and unique handcuffs.