trumpet mute aluminum practice mute trumpet for jazz, lightweight silencer for indoor trumpet practice e-riding features & benefits: application: use this aluminum mute to reduce the sound of your trumpet so you can practice whenever you want and no need worry to distract your family or neighbor! specifications: quantity: 1 pack size: inlet diameter:18.5mm/0.73 in; outlet diameter: 61mm/2.4 in; length:135mm/5.32 in. color: silver material: high-purity light weight aluminum