Very similar to Hiatt Darby Antique Adjustable Handcuffs, these come from India. The workmanship and finish are both quite shoddy but it is still unlikely that you could easily escape from them. These have been sandblasted at some point, which left them quite vulnerable to rust. They cannot be "snapped" shot without the key being screwed in at least part way because the bow isn't rigid enough to push past a fully engaged bolt. They are billed as "Hashishin" handcuffs in some ads - they aren't.