The Jo-Ral Tri-Tone Trumpet Cup Mute creates an exciting tonal quality that results in near-perfect intonation. Jo-Ral Tri-Tone mutes are made of spun aluminum, and have been tested to perform evenly in all registers. Many models are also available with brass bottoms — offering a slightly warmer, moderately dark sound — or with copper bottoms which produce an even warmer, darker, rich sound.