These are Chinese "H&R Super" style double locking handcuffs manufactured for the Chinese government. The interesting thing about these handcuffs is that the key hole is only exposed when the chain is pulled out at a right angle from the cuff.  The key engages deep down inside the cuff.  Makes them difficult to pick.

 

Patented in 1934 by Harrington and Richardson, H&R Super handcuffs were given by the USA to the Chinese government to the Chiang Kai Chek regime in their struggle with Mao Tse-Tung. When the communists won and they ran out of handcuffs, it is believed that they simply made copies, improving the lock design in the process. These handcuffs are still used by most Chinese law enforcement agencies today.

 

Weigh 16 ounces. Includes 2 keys and vinyl carrying case.