It appears to be an antique version of cufflink. Difficult to date yours with much accuracy, but I'd estimate it is from the latter-1800s to early 20th-Century. Prior to the latter 1800s, manufacturers hadn't worked out an effective way to get the tip of a "vertically mounted" tiny wire to stick to a metal surface without gobbing it up with solder or brazing.
edit: AU Seeker and I were typing at the same time.
My son thought maybe a cufflink too but we weren't sure. We had found a US Navy ring and a US Navy button in our yard so we thought maybe this item was part of the Navy uniform.