The Jo-Ral 1B Trumpet Mute is an aluminum and brass model. The acoustic design of Jo-Ral mutes creates an exciting tonal quality that results in near-perfect intonation. They are made of spun aluminum and have been tested to perform evenly in all registers. Jo-Ral trumpet straight mutes are a favorite of trumpet players at every level and in any discipline from jazz players to symphonic musicians. These free-blowing mutes provide excellent intonation and are available in a range of materials to achieve varied and distinctive sounds. In addition to out unique cork pads Jo-Ral straight mutes feature a felt cap that prevents scratching the instrument.