The mystery of the horse shoe/clip has been solved by reader Steve Renz of Superior, Nebraska.
The 61-year-old reader from Nebraska correctly identified the small device as Derby Cuff Clip.
“(It was) used to hold a cheaters card up the gamblers shirt sleeve. The horse shoe was the cuff link and the card was held by clip hidden from view of opponent,” Renz said.
Some readers incorrectly assumed the clip was used on horses, but several antique professionals – as well as a good Google search – have confirmed that the device was a cuff clip.