What is the difference between a buckle and a clasp: Buckles and straps are both used to secure watches around the wrist and can be made from numerous materials, including base metal, steel, silver, gold, platinum, or combinations thereof. A watch buckle is much like one you would find on a belt and is likely found on a strap, as opposed to a bracelet. Most buckles are of the single-tang variety, which means that there is a single hinged post fitting into a single matching row of holes (known as eyes) set into the strap. A less common version will have two tangs or hinged posts, with parallel rows of eyes to match. A clasp is more of a mechanical device and will almost always be found on a bracelet, though the concept is now also ported over to straps. The correct terminology is "deployant clasp," and they come in two versions: single and dual. Single refers to a design with one hinge, while a dual, nicknamed a "butterfly," features two hinged sections. One advantage that a clasp has over a standard buckle is that once installed, it never allows the strap/bracelet to be fully open, so that even if the clasp was to open accidentally, it is less likely that your watch would fall from your wrist. Another advantage is that when used on straps, a clasp eliminates the continual flexing required to operate a standard buckle, thus extending the life of the strap.