Button covers are like jewelry for clothes. They’re fancy buttons, often adorned with enamels and stones, that fit over standard shirt buttons, transforming even a plain white shirt into a formal garment.
The most common cufflink consists of a large head or “insert member” with a decorative front face, a post that extends from the back of the head, and a hinged toggle that swings out from the post to fasten the link. These are fastened by setting the toggle in its closed position, so that there is a straight post descending from the underside of the head. The post slides through the holes on both sides of the cuffs, and then the toggle is swung outward to prevent the post from sliding back out. That holds the cufflink in place, with the front face of the insert member placed decoratively atop the buttonholes.