Rare Kind 19c copper police thumb cuff ,The word means"Sichuan" province police supervise made .Weight :86g - eBay
I am not sure where they get 19th century and also mentioned in the listing is:
That would be 20th century. It claims to be an original and not a copy and it very well might be since eBay is not full of listings for more copies. However, the key at least is not original. And I doubt the rest is much older than the key.
This was listed with a 'buy it now' price of $80 (and $8 shipping) but it did not sell.
I still don't have any thumbcuffs but I think I will just look for a high quality new set and stay away from anything like this, unless I want something to hang on the wall. After all, who is to say that things will open up when you want them to.-----