Jo-Ral crafts the 1A tenor trombone straight mute from aluminum. 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. The ideal choice for any musical genre the Jo-Ral tenor trombone straight mute produces a distinct muted sound throughout the natural range of the instrument. It is free-blowing in all registers and designed to fit all tenor trombone bells.