Buckle keeps the band closed. They are usually made from stainless steel or titanium alloy for closing the band tightly. There are various styles of buckles and the styles of them are usually decided with the design of the watches. The major thing you need to be aware of is the width of the band decides the size of the buckle. There are several common kinds of buckles in the market: bracelet clasp, usual buckle, leather deployment buckle, hidden clasp, folding clasp with safety, hook buckle and push-button hidden clasp.