A switchblade is a folding knife with a spring mechanism that allows that blade of the knife to be rapidly unfolded with the push of a button. Switchblade knives have existed since the 18th century, but it only within the last 100 years that switchblades became associated with crime as they are today. The association of the knife with crime started with the production of stiletto-bladed switchblade- blades with a narrow, double edge- in Italy in the first half of the 20th century. Some of these switchblades were used by Italian gangs in America such as the Sicilian Mafia. The legal action against the knives did not start until the 1950s, when a number of Italian "stiletto" switchblades flooded the market, the first ones brought home by returning US soldiers in 1945. Since the 1950s, switchblades have been banned or restricted in a number of countries.