Remains of a nickel-plated Wizard Cuff Holder – a bit of late 19th/early 20th century haute-tech. These held detachable shirt cuffs in place, allowing gentleman to quickly swap filthy cuffs for new, or business white cuffs to casual stripe.
I identified this item after cleaning it up by checking the name and patent date.
That first date is October 22, 1889, and there are renewal dates up through 1906. So this one was manufactured in the first decade of the 20th century.
These are advertised as card cheating devices worn by Wild West gamblers.
Folklore suggests that the more imaginative of the Wild West poker players managed to use this gadget to hide an ace up the sleeve. With one end clipped to the clothing and the other end holding a hidden card.
THE INTRIGUING WIZARD CUFF HOLDER OF 1889, vintagecufflinksand more.com
But they aren’t. 😉