The straight mute is conical and constructed of either metal (usually aluminum)—which produces a bright, piercing sound—or another material, which produces a darker, stuffier sound. The cup mute is shaped like a straight mute with an additional, bell-facing cup at the end, and produces a darker tone than a straight mute. The harmon mute is made of metal (usually aluminum or copper) and consists of a "stem" inserted into a large chamber. The stem can be extended or removed to produce different timbres, and waving one's hand in front of the mute produces a "wah-wah" sound, hence the mute's colloquial name.