Cufflinks are used in dressy shirts in lieu of buttons on the sleeves. These male jewelry pieces are still in vogue for formal wear and require the dress shirt be made with French cuffs. These are sleeve ends which are longer than the arm to the wrist and they fall to the knuckles if not cuffed. The sleeve folded back one turn and clipped with the cufflinks through the buttonholes.
Cuffed sleeves are made to be closed with two sides together to make the sleeve end come to a stylish point. Cufflinks can have motifs on one or both sides. There is a special bar that rotates horizontally to prevent the cufflink from slipping back through the buttonholes. There are cufflinks with one decorated side such as a monogram or a jewel and then the decorated side goes on the outside. So that the decorated side is visible and the mechanism side hidden.
If you are planning to wear a formal shirt with cufflinks, it's important that the dress jacket is tailored with French cuffs. The jacket's sleeve must be roomy enough to avoid the cuffed link become squashed flat. Otherwise you run the risk your cuffs will emerge from the sleeves and they be too narrow to retreat back inside when you shoot the cuffs.
There are numerous cufflinks in a variety of styles, materials and prices nowadays. Monogrammed cufflinks always look correct. The cufflinks with emblems of trade are popular. Lodges, organizations and fraternities often supply their members with cufflinks which indicate their affiliation. Silver and platinum cuff links often suit men better though gold cufflinks look great in combination with warm colors of the suit.