Thumbscrew info

I've been trying to buy these for a year, and I was able to get them today. Does anyone have any helpful info on them? Last year I found a similar pair in a museum picture, and now I can't find it. I think it was in Scotland or France or Belgium.
Thanks.
Stan

What am I do know?

I do not know what you want me to do

John PLovell Co. 1882 Prison Cowboy Cuff. What are the worth in good condition