Snap fastener

The two halves of a riveted leather "snap"; the male half (top) has a groove which "snaps" in place when pressed into the female half (bottom)

A snap fastener (also called snap, popper, and press stud) is a pair of interlocking discs, made out of a metal or plastic, commonly used in place of buttons to fasten clothing and for similar purposes. A circular lip under one disc fits into a groove on the top of the other, holding them fast until a certain amount of force is applied. Snap fasteners are often used in children's clothing, as they are relatively easy for children to use.

Different types of snaps can be attached to fabric or leather by riveting with a punch and die set specific to the type of rivet snaps used (striking the punch with a hammer to splay the tail), sewing, or plying with special snap pliers.

In the famous Chinese Terracotta Army, dating from 210 BC, the horse halters of wagons, made of a gold tube and a silver tube, were joined with a form of snap fasteners.

Modern snap fasteners were first patented by German inventor Heribert Bauer in 1885 as the "Federknopf-Verschluss", a novelty fastener for men's trousers. Some attribute the invention to Bertel Sanders, of Denmark. These first versions had an S-shaped spring in the "male" disc instead of a groove. When Jack Weil (1901–2008) modified the design and put snaps on his iconic Western shirts, the term "snap" became commonplace and snap fasteners came into use in much Western wear.

In Western fashion

Roy Rogers wearing Western shirt with pearl snaps

Press studs were worn by rodeo cowboys from the 1930s onwards, because these could be quickly removed if, in the event of a fall, the shirt became snagged in the saddle. Pearl snaps entered mainstream Western fashion during the 1950s, when singing cowboys like Gene Autry and Roy Rogers incorporated them into their embroidered and fringed stage shirts. The most desirable shirts were unique creations tailored by Nudie Cohn or Rodeo Ben, but commercially produced Western clothing could be purchased from companies like Wrangler, Levi Strauss, Panhandle Slim, Rockmount Ranch Wear, H Bar C, or Roper.

Due to the popularity of Spaghetti Westerns, cowboy shirts with oversized collars were widely worn by teenagers and young adults from the mid 1960s until the early 1980s. By the 1990s, however, press studs had become associated with the adaptable clothing worn by pensioners and the disabled. During the late 2000s and 2010s, however, shirts with Western detailing made a comeback in Europe and the southern US due to the popularity of indie rock and a resurgence of interest in vintage Americana.