A silencer, also known as a suppressor, is a device attached to the muzzle of a firearm to reduce the noise generated when the gun is fired. It works by slowing and cooling the escaping gases from the bullet, which decreases the sound produced. Silencers are often used in shooting sports, hunting, and by law enforcement to minimize noise pollution and improve accuracy. In many countries, the legality of owning a silencer varies. In the United States, for example, they are regulated under the National Firearms Act and require a special tax stamp for ownership. Silencers do not make guns completely silent but can significantly lower the sound level.