Here is a picture of the writing.

and here is a close up of the cuffs.

Adjustable prison shackles ... "Alcatraz" was the model, I think. One pair sold on eBay for $50 recently

Prisoners were shackled when they were being moved, so there are lots of these around.

Thought I answered this 1. Alcatraz Island is off San Francisco CA. Big prison used to be there. So you might look under collectibles from prisons or that one . It is open for tours, son visited last yr. Interesting but very bleak. Iron & concrete everywhere. Surrounded by water as worse prisoners there." Birdman from Alcatraz "with Burt Lancaster, I think was movie made from the book!! You must be young!! I thought everyone in world knew of that terrible place!

Here is a link to an eBay auction for some like yours that ended on July 13, at $82.11.

Here is a link that might be useful: ANTIQUE IRON RESTRAINTS ALCATRAZ PRISON INMATE SHACKLES AL CAPONE'S PRISON